### Scribe Post for May 20, 2010

Thursday, May 20, 2010
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!

Wednesday, June 10, 2009
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 :]

Sunday, May 31, 2009
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!

### Percents Homework Assignment

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

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

Saturday, May 30, 2009
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.

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.