Math Blog 816 (2008)

Scribe Post for May 20, 2010

noreply@blogger.com (Unknown) — Thu, 20 May 2010 23:46:00 +0000

Hello there, 9-05! Today we started on Chapter 10 which is Circle Geometry. We went straight to 10.1 and started learning or reviewing about circles since I'm sure most of us know something about circles. Chapter 10.1 is about Exploring Angles in a Circle. For this class, we spent our time taking down notes and Mr. B taught us how to find angles.

Circumference - The boundary of or distance around a circle.
Diameter - The distance across a circle through its centre.
Radius - A line segment joining the centre of a circle to the outside edge.

The angles ABC is called a Central Angle.
Central Angle - An angle form by two radii of a circle.
The straight yellow line from A to C is called a chord.
Chord - A line segment joining two points on the circumference of a circle.

Angles ADC and AEC are examples of Subtended Angles.
Subtended Angle: Lying opposite to.
Inscribed Subtended Angle: is equal to half the central triangle.

How do you find the measurement from B to C? Use Pythagoras!
First of all, why do we use Pythagoras? We can use Pythagoras method as long as there is a right triangle to find out the missing side length. Do you see the right triangle? If you flip it over or turn your head upside down, you will be able to see a right triangle. So, the angles AC will be represented as the hypotenuse which is c. And let's say that AB represents a and BC represents b.
a^2+b^2 = c^2
6^2+b^2 = 10^2
36+b^2 = 100
b^2 = 100-36
b^2 = 64
Square root b^2 = Square root 64
b = 8
The missing measurement of the line B to C is 8 cm.

Homework:
Chapter 10 Warm-Up #1
10.1 Textbook
-Practice, all odd
-Apply, all even
-Extend and any 2
10.1 Workbook
10.1 Worksheets

Well, that is all for now folks! (: I hope you enjoyed my post! Keep working hard 9-05! For exams are coming soon and we only got about a month of school left! The next scribe is KIM (:
Okay tootles!

noreply@blogger.com (Unknown) — Wed, 10 Jun 2009 21:19:00 +0000

My video was made on animal cruelty. I did the project with Jessica and Katlyn. It shows what animal cruelty is and the easy steps that you can do to help stop it. Enjoy! :)

For additional information check out these websites:

http://www.hsus.org/acf/cruelty/
http://www.youthnoise.com/page.php?page_id=2583

percents :]

noreply@blogger.com (Unknown) — Mon, 01 Jun 2009 04:24:00 +0000

So here are my percent questions that Harbeck is making us do.. OUR LAST POST IN GRADE 8!

Anyways so here they are. Enjoy! :]

Sorry.. im super lazy and super tired so im not going to do it all fancy smancy. :]

1)
245% of 356.80$

356.80$/ 100 = 3.568

3.568 x 245 = 874.16

2)
68 3/4% (68.75) of 730

730 / 100 = 7.3

7.3 x 68.75 = 501.875

3)
360% of $129.95

129.95 / 100 = 1.2295

1.2295 x 360 = 467.82

4)
63% of $345 0000

345000 / 100 = 3.45

3.45 x 63 = $ 217.35

5)
182% of 1700

1700 / 100 = 17

17 x 182 = 3094

ALL DONE!

Charissa's Percent Post

noreply@blogger.com (Unknown) — Mon, 01 Jun 2009 02:30:00 +0000

Percents Homework Assignment

noreply@blogger.com (Marc905) — Mon, 01 Jun 2009 01:32:00 +0000

This post is about finding the percentage of a certain number. On Friday Mr.H assigned a whole page of questions and problems that were to be due on Monday, June 1st, which is tommorow.. but he gave us a deal that if we made a post of the home work, then we don't have to do all 9 questions but only five. For this post I made a slide show because I think it's the most easiest to make, so.. ENJOY!

Percents Homework Assignment

noreply@blogger.com (Eunice 8-16) — Sun, 31 May 2009 19:12:00 +0000

Eunice Cadao
8-16

Hello! On Friday Mr. Harbeck assigned us a math homework, which is to be our last blog post. He gave us an option. We could do all of the questions or do only 2 questions and number 4.

Part A
1) 245% of $356.80

2) 68 3/4% of 730

3) 360% of $129.95

Question 6:
Table salt is a chemiccal compound of sodium and chlorine. Recommended daily intake is about 1700 mg. If Canadians consume 182% of this amount on average, how much sodium is one person eating.

Question 8:
The Nile River is about 209% of the length of the Yukon River. If the Yukon River is 3168 km, how long is the Nile River (to the nearest km) Show your work.

Percent Post

noreply@blogger.com (Unknown) — Sun, 31 May 2009 03:30:00 +0000

Percent. It's an ugly word with an uglier place in mathematics. Here are some examples.

Let's say you're working at an office. Normally, the people in the office are okay (except that creepy, rat-like weirdo who chews on your pencils) and your boss is pretty mellow. Now, one day, your boss is feeling a bit hung over from the previous night (his wife left him). So now, feeling pretty crappy and bitter, he decides to take his pent up anger out on you. So, when you don't expect it, he takes the coffee pot and dumps the scalding contents on your head. Realising what he's done, he quickly reacts and decides to increase your pay check as compensation. By 245%.

Now here's the question:

What is 245% of $356.80 (your original paycheck)?

To find this, you merely find 2x (200%) your paycheck, add half the amount of your original pay and subtract 5%.

Doing the first step is easy, just multiply you check x2.

So, 200% of %356.80 is... $713.60!

When we add half of your original amount, which is 178.40, you get $892.

Now, when we subtract 5%... you get $847.4.

You may not be able to build that hi-tech home entertainment system, but at least you can make rent this month. Not too bad.

Here's another example in the form of a word problem.

Let's say you quit your old job and are in need of some money. You only have $129.95 and are pretty desperate. One night at a bar, you make a bet with your friend: You bet the last of your money that you can consume more shots than he can. If you do you get X% of your money. X being the number of shots you drank times 1o.

Twenty minutes later, you and your friend are neck in neck. Your drinking buddy suddenly doesn't feel so good. And a few seconds later, he pukes. You have officially drank him under the table and you have consumed 36 shots. You get 360% of your original $129.95.

How much did you receive?

To find the answer, you have to find your amount of money times 3, then add 3/5 of the original amount to the result.

I'll show you. First to find the 300%. That's simply 3x the $129.95.

129.95 x 3 = $389.85

Now that we have the 300, we need to figure out the 60. The 60 is equal to 3/5 of 129.95.

We can also achieve 60 by subtracting 40%.

So, 129.95 - 40% = $77.97

Now, just add the two together and you get $467.82.

Okay, here's your next question. After your buddy has waken up from his alcohol-induced state you both go home. When you get back to your apartment, you do what you always do: log on to your laptop. Tonight, you decide to play an MMORPG with friends. You are a half-orc barbarian, 18 STR, 16 DEF, 2 CHAR, etc. (To those who can't understand what these mean, LEARN TO PLAY NOOBS.)

Anyway, your walking through a forest, your boots cracking the twigs with every step. You then see something out of the corner of your eye. You turn and find a glowing flower on the side of the path. While going over to inspect it, a fairy suddenly pops out. It's holding a large sword. It offers it to you in exchange for a certain percentage of your gold. You have 730 gold and the fairy demands 683/4 % of it. Do you accept the deal?

Okay, first you have to find out what 60% of 730 is, what 8% of it is and what 3/4 of a percent it is.

First, the 60. That's easy, 730 - 40% = 438

Now for the 8. 730 - 92% = 58.4

Finally, the 3/4. To find this, you need to find 1%, divide it by 4, and multiply the product by 3.

730 - 99% = 7.3

7.3 / 4 = 1.825

1.825 x 3 = 5.475

Add your three results together (5.475, 58.4, 438) you get 501.875 gold.

You decide to give him most of your hard earned gold and in return you get a High Quality Long Sword. Now you can kill those annoying goblins.

Now after you completely pwn'd that goblin hoarde and ultimately got beaten out at 2 am by the blue screen of death. You then, reluctantly go to sleep.

1 pm. You are abruptly awakened by the buzzing sound of your alarm. You shut it off and then realize what time it is. Then you realize where you're supposed to be. You quickly burst out of bed, run into the door in your confused state and then get dressed. You then, get yourself to the balcony and slide down the fire escape into your car. You speed your way to the arena. You almost forgot the hockey game you were supposed to go to.

Second period. Half time. You just saw the Toronto Maple Leafs score their third goal against the New Jersey Devils. Now it's time for the half time contest. The announcer goess to the ice and calls out the following position. He says Section A, Row 2, Seat 12. Your seat. You quickly get out and onto the ice. The announcer asks you the following question:

"This arena seats 4900 people. Tonight, only 63% of the arena is filled. How many people are seated in the arena?"

There is an easy way to solve this. There are 4900 people in this arena. Divide the 4900 into 49 100's. Or, 49 wholes. Out of that 100, 63 of the seats are taken. Multiply that 63 by 49 and you get 3087.

After this mental math you quickly answer 3087. The announcer says you are completely right.

Congradulations! You have just won tickets to the Stanley Cup Finals!

On your way home from the game, with your newly claimed prize, you find your friend Miguel. He looks pretty freaked out. He says he just bought a Maxima for $4700. Now, here's the trouble. Miguel completely failed his math when it came to percents. The dealer said he had to pay a down of 19 1/2 percent of the total $4700. Can you help him?

This problem can be solved the same way as the last one. Just divide the 4700 into 47 groups of 100. Then subtract 19 1/2 from each group. That is equal to 19 1/2 x 47. 19.5 x 47 = 916.5

Miguel has to pay $916.50 to get his Maxima.

Francis 2 minutes to make a difference on WORLD HUNGER

noreply@blogger.com (Unknown) — Wed, 27 May 2009 01:55:00 +0000

Me, Jay and Marc did a movie explaining how terrible it is to be involve in World Hunger. This video tells you different things that Hunger already did to us and how YOU could help stop it.
Watch it with feeling and see how bad it can do to us.

WORLD HUNGER

Many organization are helping fight this.

CAN YOU?

UofR Regina, Sk.

noreply@blogger.com (Tiffany (University of Regina)) — Mon, 25 May 2009 03:17:00 +0000

Hi everyone,
I am Tiffany, a fourth year university student at the University of Regina. I am studying to be a Math and Science teacher, so when I finish up at university in two years I will be looking for my own classroom to teach Math in. I am excited to check out your blogs and read about what you are learning and also to see how math makes it onto the internet with your help. To be honest, I have never heard of a math blog before, because when I was in Grade 8 there wasn't such a thing. But I think it is a great idea! Well, I think this tells a little bit about me and where I am at in my education. Looking forward to seeing your work! Cheers.

Trent 2 minutesto make a difference

noreply@blogger.com (Trent) — Thu, 21 May 2009 12:10:00 +0000

Me Brendyn and Zack decided to make our video about poverty and what it does to people. Also some ways we can put an end to it once and for all because...
none deserves to live like they do.

Animal Abuse 2 Minuites to Make a Difference

noreply@blogger.com (Jessica16) — Thu, 21 May 2009 02:51:00 +0000

Charissa, Katlyn and I made our video about animal abuse. It explains a few different kinds of abuse, as well as how you can help stop animal abuse.

Countless numbers of animals are killed each year because of animal cruelty..
Animal cruelty needs to be stopped.

If you want to learn more about animal cruelty, go to these sites:
http://www.hsus.org/acf/cruelty/
http://www.elmorehumane.com/Animal%20Abuse%20Info.htm
http://www.geocities.com/paws_n_tails/AnimalTestingFacts.html
(Just so you know ahead of time, some of the pictures in these sites are graphic.)

Christian's 2 minutes to make a difference

noreply@blogger.com (Unknown) — Thu, 21 May 2009 01:17:00 +0000

Well my group, The Pocket full of Awesomeness, decided we should do our video about air pollution. Air pollution is a big topic, we had a lot of information, good pictures and an appropriate music. The video has imformation like what and who caused it? and like what can one person do to help make a difference or even just help prevent it from happening.

Melissa's 2 Minutes to Make a Difference

noreply@blogger.com (Unknown) — Thu, 21 May 2009 00:15:00 +0000

For my groups 2 minutes to make a difference project, we did our project on air pollution. In this video, there will be information about how air pollution is caused, who and what does it affect, and how we can help to save the earth.

Marc's 2 Minutes to Make a Difference

noreply@blogger.com (Marc905) — Wed, 20 May 2009 23:04:00 +0000

For the 2 Minutes to Make a Difference project, our main topic was World Hunger. This video is about how many people die of everyday hunger, and many of those people are just children. This video includes many interesting facts about world hunger, which part of the world is most likely to be suffering from world hunger, and what we can do about it.

Abby's 2 Minutes To Make A Difference

noreply@blogger.com (Unknown) — Wed, 20 May 2009 21:38:00 +0000

The topic my group and I chose for the 2 Minutes to Make a Difference project was air pollution. The video here is about, of course, air pollution. Included in the video is some facts about how air pollution affects the health, what it does to our earth, and how to prevent air pollution.

child labour: 2 minutes to make a difference

noreply@blogger.com (Unknown) — Wed, 20 May 2009 04:56:00 +0000

Rayna, Samantha, Kelsey, Gennia... 8-16

Child labour is so cruel! No child deserves to have their child hood taken away for them and be forced to work crazy long hours, at crazy young ages. Child labour needs to stop and it starts with one!

Last Fraction Post

noreply@blogger.com (jessP,816) — Wed, 13 May 2009 20:16:00 +0000

Last Fraction Post

noreply@blogger.com (Unknown) — Wed, 13 May 2009 04:09:00 +0000

This is my Last fraction Post. What the fraction post suppose to be about is explain what we learned about fractions. Like how to add, subtract, multiply and divide fractions.

I dont think im completely done. So sorry (: i tried my best.

Katlyn and Charissa's last fractions post!

noreply@blogger.com (Unknown) — Wed, 13 May 2009 03:34:00 +0000

Hey sorry its late but we forgot to post it yesterday! So here it is..ENJOY!

Adding Fractions
Adding fractions is pretty easy, just follow these step and you'll be good to go!

Sorry its a link people but I don't know how to post google docs in blogger so, SORRY!

Last Fraction Blog Post

noreply@blogger.com (jaymie) — Tue, 12 May 2009 23:52:00 +0000

Addition
Adding fractions is easy once you get the hang of it you can get subtraction as well. First you have to make all your fractions improper to start here is the first example.

So first you make the fractions improper but since these are proper fractions we have no need to. Next you have to find the common denominator ( which means the number both denominators go into.) Which in this case is 10. So you change both numerators to 10. Next you think what multiplied by 5 gives you 10 the answer is 2 so you multiply the numerator (2) by 2 which gives you your first fraction which is 4 over 10. Now do the same with the other fraction. What multiplied by 10 equals 10 hmm I'm pretty sure its 1 multiplied by 10 = 10 so you times the top number (3) by 1 which is 3 so the fraction is 3 over 10.

Now that you have your fractions you just add the numerators together.

So you answer is seven tenths! we always have to simplify but we don't have to now.

Hes exited for the next question are you!? Next addition question!

First we find the common denominator which in this case is 9 because 3 and 9 go into 9. so now we change both denominators to 9. We can keep the first fraction the same because it is being multiplied by 1 which makes that fraction 5 over 9 . but the other you need to think what time 3 is 9? 3 times 3 is 9 so you times the top number(1) by 3 which equals 3 so that fraction would be 3 over 9. Add the numerators together and you get your answer.
Subtraction
You do the same steps that you do in adding than you do in subtracting except instead of adding at the end you subtract. This example is a mixed fraction.

Im sorry im not done :(

.

Jay's Last Fraction Post

noreply@blogger.com (Unknown) — Tue, 12 May 2009 05:15:00 +0000

Patrick's Last Fraction Post

noreply@blogger.com (Patrick 8-16) — Tue, 12 May 2009 02:12:00 +0000

Hey Everyone! Last fraction post here and I'm gonna show you how to add, subtract, multiply and divide fractions! Let's start with adding!

Here's an example: 2/4 + 1/4
Since the denominators are the same, all you have to do is add the numerators together.
2 + 1 is 3 so... 3/4!

What if the denominators weren't the same?? :O! Well it's still easy! :) Just MAKE the denominators the same!
For example: 2/4 + 2/8
Now, how do you make the denominators of 4 and 8 the same? Divide 8 by 2! 8 divided by 2 is 4, which is the same as the other denominator. And whatever you do to one side, you do to the other. Now you have to divide the numerator by 2 'cuz you did it to the bottom. The numerator is 2 so 2 divided by 2 is 1. The fraction is 1/4!
2/4 + 1/4 = 3/4 ...hard? I think not!

Subtracting Fractions isn't very hard neither. I'll give you one example with the same denominators and another with different denominators.
Example 1: 4/10 - 2/10
Just subtract the numerators since denominators are the same. 4 - 2 = 2. 2/10 is the answer.

Example 2: 4/10 - 6/30
The denominators are 10 and 30. Divide 30 by 3 to equal 10, an equal denominator to 10! Whatever you do down there, you do up there, too. Divide 6 by 3 to get 2. The equation is 4/10 - 2/10 = 2/10

Multiplying Fractions gets a bit complicated, but not if you know what you're doing.
Example 1: 2/3 x 4/5
The first step is to multiply the numerators. 2 x 4 equals 8. Then multiply the denominators. 3 x 5 equals 15. Your fraction is 8/15! EEEEAASSYYY!!....if you know how to do it :)

Example 2: 2 1/2 x 1/2
Woah! That's hard, eh? NOT! Do you know what an improper fraction is? It's a fraction that has a greater numerator than denominator, meaning its total value is more than 1 whole. All you need to do is convert 2 1/2 into an improper fraction, then use the 2 steps from example 1! To convert a mixed number into an improper fraction, multiply your wholes (2) by your denominator (2) and then add it to your numerator (1). 2 x 2 = 4 + 1 =5. Then use the same denominator. 5/2 is the fraction so you're multiplying 5/2 by 1/2. Multiply Numerators (5 x 1 = 5) and denominators (2 x 2 = 4) to get the fraction 5/4. That's your answer!

Everything is easy so far, right? Well, how do you think dividing will be? EASY! I'll teach you on the way!
Example 1: 9/10 ÷ 3/4

The reciprocal is just a way to find the answer easier. The question is 9/10 ÷ 3/4. Take 3/4 and multiply it by its "opposite". 3/4 x 4/3 is 1 whole. Whatever you do down there, you do up there. Now you multiply 9/10 by 4/3 because you did it to the bottom fraction. Your answer is shown above. Just simplify the improper fraction into a mixed number.

Example 2: Mixed Numbers!
3 1/2 ÷ 7
First, convert your mixed number!
Whole x denominator + numerator...
3 x 2 = 6 + 1 = 7
7/2 is your fraction.
You also have to convert the 7. Let's use the denominator of 2! 7 x 2 is 14. 14/2 is 7 wholes!
7/2 ÷ 14/2 ...use the reciprocal now!

Dividing fractions isn't so bad...

Now let's get to word problems :)

#1: It takes 2 1/4 scoops of flour to make one cake. How many cakes do 15 scoops make?
Let's draw pictures!

As you can see by the indicated colors, 15 scoops of flour can make 6 cakes and 2/3 of a cake.

#2:
One day in Winnipeg with 10 1/2 hours of daylight, it was sunny for 1/3 of that time. For how many hours was it sunny that day?
Convert 10 1/2 into improper to make it easier...
10 x denominator (2) + numerator (1).
10 x 2 = 20 + 1 = 21
21/2 is equal to 10 1/2.
We're trying to find 1/3, so just divide it by 3 if you can, and take 1 piece because you have 1 thirds.

3 1/2 hours of that sunlight were sunny on that day in Winnipeg, out of 10 1/2 hours.

Oh! Before I go, remember to always simplify your fractions if possible, and to always have simple sentence answers to any word problem! Cya guys later!!

Eunice's Last Fraction Post

noreply@blogger.com (Eunice 8-16) — Tue, 12 May 2009 01:17:00 +0000

Gian's last fraction post

noreply@blogger.com (Unknown) — Tue, 12 May 2009 01:01:00 +0000

Multiplying and Dividing Fractions

Question 1

Our first question is 2/3 multiplied by 9/10. First what we do is to multiply the numerators which is 2 and 9. So 2 x 9 equals to 18.

Now all that is left to do is to multiply the denominators. So 3 multiplied by 10 equals to 30.

Now the fraction we have is 18/30. So we simplify it and we get 3/5.

So our answer is 3/5 .

Question 2

Now we move on to dividing fractions. Our first Question is 1/4 divided by 3/4. When dividing fractions it always helps when using a ratio table.

Now we have to make it into a mixed fraction. First we have to figure out how many times does 4 go into 12 ? 3 , so 3 becomes the whole number. Since 4 goes into 12 perfectly and there are no left over 3 also becomes our numerator and the denominator stays the same.

Adding and Subtracting Fractions

Question 1

First what we do is look at the Denominators. Then we look at what the two Denominators both go into, then we multiply. 2 multiplied by 7 would give us the total of 14.

Now that we multiplied both our numerators. All that is left to do is add both second fractions that we got which was 7 over 14 and 4 over 14.

So all we did for the last step was add the numerators and kept the denominators the same, which gave us the total fraction of 11 over 14.

Question 2

First we look at the Denominators, then we figure out what they both go into so 3 times 10 equals 30. Now we make a set of fractions that could go into 30. Now we divide. We divide 3 into 30 and also divide how many times 10 goes into 30.

The last thing we do now is to take away from the numerator which is 10 and 9. So 10 take away 9 equals to one. Then we keep the denominators the same and we have a fraction of 1 over 30.

Word Problems

Question 1

Question 2

Question 3

Marc's Last Fraction Post

noreply@blogger.com (Marc905) — Tue, 12 May 2009 00:03:00 +0000

Adding Fraction:

Well what I've learned about adding fractions from all the teaching Mr.H taught us, I actually found that adding fractions were simple. Just like 1 2 and 3

And just like I said...1

Perhaps the question was 5/9 + 1/3..
The first step would be to do cross multiplication...

Then....2

you then simply add the two numerators(15 and 9)

and the last step......3

To simplify your answer to the lowest terms, you find the number that is able to divide the numerator and denomerator and the number happens to be 3...

Subtraction is the exact same thing as adding fractions but at the second step you just subtract instead.

Now for adding when you have a mixed number is also very simple, if you think that adding fractions were difficult at this point you must be crazy.

Adding Mixed Fractions

Step 1:

Perhaps the question was....2 4/9 + 5 1/2
You just add the whole fractions together first (2 and 5) which will equal 7

now what would be left is 4/9 and 1/2, so now you do the procedure as if this question was like the very first one in this post.

Your answer should now be 17/18 and all you do now is put the two answers together which would become 7 17/18

Now here's a presentation for multiplying and dividing fractions....

This is the end of my final post for FRACTIONS

~THE END~