## Tuesday, November 30, 2010

### John Chua's scribe post

Understanding percents.
DEFINITIONS:
Percent- means it is out of a hundred or another name for hundredths
eg. 65% means 65 out of a 100 or 65/100 or o.65

Fractional percent- a percent that includes a portion of a percent.
eg. 1/2%, 0.42%, 7 3/8%, 125 3/4%, 4.5%

SHOW YOU KNOW:
page 125

A) 248% B)1/4% C)74 8/10%
Page 127

A)

B)

C)

## Thursday, November 18, 2010

### Maya's Text Book Pages

Questions 3, 7, and 11. Pages 110 - 111

3. Walter walks across a rectangular field in
a diagonal line. Maria walks around two sides of the field. They meet at the opposite corner.

7. What is the height of the wheelchair ramp? Give your answer to the nearest tenth of a centimetre.

The answer is 12.6

11. Johan has a 300cm ladder that he leans up against a wall. The safety sticker on the side of the ladder shows that the bottom must be placed between 70 cm and 110 cm away from the wall. What are the minimum distance and maximum distance up the wall that the ladder can reach? Give your answers to the nearest tenth of a centimetre.

The answer is 291.7 cm.

Here are two videos that may help you.

Here's a link to also help you.

### Louis' Homework book: 30 questions 2, 3, 4

Homework Book Pages 30 questions 2, 3, 4

2) Use the relationship to determine the length of C in each triangle, to the the nearest whole number. Show your work.

A)

b2=c2 - a2
b2=262 - 242
b2=676 - 576
b2=100m2

square root 100 m2 and it becomes 10m

B)

a2=c2 - b2
a2=392 - 152
a2=1521 - 225
a2=1296 cm2

square root 1296 cm2 and it becomes 36cm

3) Determine the length of each hypotenuse. Show your work.

A)

a2 + b2 = c2
402 + 92 = c2
1600 + 81 = c2
1681 cm2 = c2

square root 1681 cm2 and it becomes 41cm

B)

a2 + b2 = c2
352 + 122 = c2
1225 + 144
1369m2 = c2

square root 1369 m2 and it becomes 37m

4) What is the length of each hypotenuse, to the nearest centimeter? Show your work.

A)

a2 + b2 = c2
82 + 92 = c2
64 + 81 = c2
145 = c2

square root 145 cm2 and it becomes 12.04cm

B)

a2 + b2 = c2
102 + 62 = c2
100 + 36 = c2
136 cm2 = c2

square root 136 cm2 and it becomes 11.66 cm

### Jennily's Textbook Pages

Pg 108-110

Question 3,9,11

3. Walter walks across a rectangular field in a diagonal line. Maria walks around two sides of the field. They meet at the opposite corner. Express your answer to the nearest metre.

A) How far did Maria walk?

B) How far did Walter walk?

C) Who walked further? By how much?

A) Maria walked 420 Km.

B) Walter walked 323 Km.

C) Maria had walked more further by 97m.

9. A checkerboard is made of 64 small squares that each have a dimension of 3cm * 3cm. The 64 small squares are arranged in eight rows of eight.

A) What is the length of th diagonal of small square? Give your answer to the nearest tenth of a centimetre.

B) What is the total length of the diagonal of the board? Give your answer to the nearedt centimetre.

A) a square + b square = c square

3 square + 3 square = c square

9+9=18

c square = 18

c = 4.2 cm square

B) 32cm
11. Johan has a 300-cm ladder that he leans up against a wall. The safety sticker on the side of the ladder shows that the bottom must be placed between 70 cm and 110 cm away from the wall. What are the minimum distance and maximum distance up the wall that the ladder can reach? Give your answers to the nearest tenth of a centimetre.
The maximum is 291.7 cm, and the minimum is 279 cm.

## Tuesday, November 16, 2010

### Meldrick's Textbook Pages

The pages I had to do 7, 10, 13, and the deadly question 16.

Number 7
What is the missing length of the leg for each triangle? Give your answer to the nearest tenth of a millimetre.
a)

a²+b²=c²
a²+5²=9²
a²+(5x5)=(9x9)
a²+25-25=81-25
a²=56 mm²
√a²=√56 mm²

a=7.5 mm

b)

a²+b²=c²
a²+11²=15²
a²+(11x11)=(15x15)
a²+121-121=225-121
a²=104 mm²
√a²=√104
a=10.2 mm

Number 10
What is the minimum distance the player at third base has to throw to get the runner out at first base? Express your answer to the nearest tenth of a metre.

a²+b²=c²
27²+27²=c²
(27x27)+(27x27)=c²
729m²+729m²=c²
1458m²=c²
√1458=√c²
38.2m=c

The player must throw a distance of 38.2 metres.

Number 13
Determine the length of the base of the large triangle. Express your answer to the nearest tenth of a millimetre.

a²+b²=c²
8²+b²=10²
(8x8)+b²=(10x10)
64-64+b²=100-64
b²=36mm²
√b²=√36
b=6mm
b(2)=6(2)

Base=12cm

Number 16
The deadly number 16. Hopefully you won't need this guide, as it is for people who have been reduced to tears (not literally) by this question. But if you are one of these people, you are welcome to look at the answer.
What is the length of the red diagonal in the box? Express your answer to the nearest tenth of a millimetre.

Now, imagine that the triangle has been cut in half, from the top right corner to the bottom left corner, so that the diagonal is on a 'flat surface'. Using the height (5mm) and length (12mm), we can find the hypotenuse of the 'triangle' that was created when the rectangle was cut in half, using the Pythagorean theorem (height-a, length-b):
a²+b²=c²
5²+12²=c²
(5x5)+(12x12)=c²
25+144=c²
169cm²=c²
√169=√c²
13mm=c
After that, imagine turning the triangle so that you can see the red diagonal cutting a rectangle in half. You have already found the bottom of the rectangle (13mm), and you have the measurements for the right side of the rectangle, the width (7mm). Using the Pythagorean theorem, you can now find the red diagonal (width-a, bottom-b).
a²+b²=c²
7²+13²=c²
(7x7)+(13x13)=c²
49+169=c²
218cm²=c²
√218=√c²
14.8cm=c

Hopefully, you found that helpful. Good night (it's 1:05 AM), and goodbye.

### Textbook Work

Textbook
I had to do numbers
5, 8, 11, and 14

5)

B)
The area of the square attached to the hypotenuse is 100

C)
The length of the hypotenuse is 10

14)
c²-b²=a²
5²-3²
25-9=a²
16m²=a²
√16m²= √a²
4m=a
**The √ are suppose to be square root signs.**
If you guys still don't understand what a hypotenuse is, maybe this video might help.

Here's a link to help you guys!

### Mussie Mesgun Homework Book: Even Questions

2) Use the relationship to determine the length of C in each triangle, to the nearest whole number.show your work.

A) a²+c²=b²
24² cm 26² cm=c²
-576 cm + 676 cm=c²
100 cm=c²
√100 cm=√c²
10cm=c

B) a²+c²=b²
39² +15²=c²
1521 + 225 =c²
√1746=√c²
41.78 =c
42 = c

4)What is the length of each hypotenuse, to the nearest centimetre? show your work

A) a²+b ²=c²
8² cm + 9² cm=c²
64 cm +81cm=c²
√145cm =√c²
12.0cm=c

B) a²+b²=c²
6² cm +10² cm=c²
36 cm+100 cm=c²
√136cm²=c²
11.6 = c
12 = c

6) Find the height of triangle with a base of 4 cm and a hypotenuse of 11 cm. Round to the nearest tenth of a centimetre. show your work

a²+b²=c²
-4² cm +11² cm=b²
-16 cm +121cm=b²
√105cm=b²
b=10.2
b = 10 cm

8) Ellie and Lucas are going to the skateboard park to try out the new ramp.

A) is the new ramp a right triangle? explain your thinking

Yes is a right triangle because it as a 90' angle

### Using the Pythagorean Relationship, Homework Book

1. RED is the answer
The Pythagorean relationship can be used to determine the Length of the Hypotenuse of a right triangle when the lengths of the two Legs are known.

3. Question - Determine the length of each hypotenuse. Show your work.
a)
a squared + b squared = c squared
40cm squared + 9cm squared = c squared
(40x40) + (9x9) = c squared
1600cm + 81cm = c squared
The square root of 1681cm = c squared
41 cm squared = c squared

b)
a squared + b squared = c squared
12m squared + 35m squared = c squared
(12x12) + (35x35) = c squared
144m squared + 1225m squared = c squared
The square root of 1369m squared = c squared
37m squared = c squared

5. Question - Calculate the missing side length for each right triangle, to the nearest tenth of a centimetre. Show your work.

a)
a squared = c squared - b squared
a squared = 6 cm squared - 5 cm squared
a squared = (6x6) - (5x5)
a squared = 36cm squared - 25cm squared
The square root of 11 = a squared
a squared = 3.31cm squared

b)
a squared = b squared - c squared
a squared = 7cm squared - 12cm squared
a squared = (7x7) - (12x12)
a squared = 49cm squared - 144cm squared
The square root of 95 = a squared
a squared = 9.74

7. Question - A triangle is made up of two smaller congruent right triangles.

a)
a squared + b squared = c squared
4m squared + 2m squared = c squared
(4x4) + (2x2) = c squared
16+ 4 = c squared
The square root of 20 = c squared
4.5 = c squared

b)
a squared = c squared - b squared
a squared = 8m squared - 4.5 squared
a squared = 8m squared + 4.5m squared + 4.5m squared
a squared = 17m squared

SORRY ITS SO LATE GUYS :)
BY:KRIS G
ROOM:8-73

### Joshua's Pythagoras Scribe Post

6. Determine the length of the leg for each right triangle.

9. Tina wants to construct a path along the diagonal of her yard. What length will the path be? Express your answer to the nearest tenth of a metre.

12. The hypotenuse of the triangle cuts the circle in half. What is the diameter of the circle? Express your answer to the nearest tenth of a centimetre.

15. The coordinate grid shown was drawn on centimetre grid paper. What is the line segment of AB? Express your answer to the nearest tenth of a centimetre.

Here is a video to help you:

Here is a link to help you.
If I made any mistakes, please tell me!

## Monday, November 15, 2010

### Hazel's Pythagorean Relationship Scribe Post

Key Ideas

The Pythagorean relationship can be used to determine the length of the hypotenuse of a right triangle when the lengths of two legs are known.

The Pythagorean relationship can be used to determine the leg length of a right triangle when the lengths of the hypotenuse and the other leg are known.

1. Jack must determine the missing side of a triangle. He decides to draw it and then measure it,as shown. Do you agree with the method that Jack is using? Explain.

Answer: No, I don't agree with the method that Jack is using because it would take too much work. It would be easier if he just used the formula: a²+b²=c² then √c²=c (hypotenuse).

2. Kira calculated the missing side length of the right triangle.
Is Kira correct? If she is correct, explain how you know. If she is incorrect, explain the correct method.
Answer: Kira is incorrect. She should've used the formula b²=c²-a² or in this case, y²=x²-w².

3.Determine the length of the hypotenuse.

4.What is the length of each hypotenuse? Give your answer to the nearest tenth of a centimetre.

Here is a
link to the textbook website.
Here is a
link to a pythagoras website.

## Friday, November 12, 2010

### Maya's Text Book Scribe Post

# 10 and 16.

Page 98
10) Kai uses an entire can of paint on a square backdrop for the school play. The label on the can states that one can covers 27m² of wall surface. Estimate the backdrop side length, to one decimal place.

Answer:
5.2 is the estimation of 27m².

Page 100
16) A tub in a fitness centre will install a square hot tub in a 6 m × 6 m room. They want the tub to fill no more than 75% of the room’s area.

a) What is the maximum area of the hot tub?

Answer:
The maximum area of the hot tub is 27m
²

b) What dimensions, to a tenth of a metre, will the fitness centre order from the manufacturer? Explain.

Answer:
The dimensions should be 5.1 by 5.1 so the area does not exceed 75% of the space available.

*Sorry if I didn't explain it well.

Here's a video to help you estimate square roots.

## Wednesday, November 10, 2010

### Samarab 8-73 Textbook Post

Pg. 98 and 100

6) What is an example of a whole number that has a square root between 9 and 10 ?

Answer: 90. 90 is a possible answer .

9) What are the possible whole numbers that has a square root between 4 and 5 ?

Answer : 17,18,19,20,21,22,23,24 . All theses are the possible answers .

### Krizna's Textbook Post

Pg.100
Questions 7 and 8
7.Identify a whole number with a square root between 11 & 12
Answer: the square root of 11 is 111 and the square root of 12 is 144 the square root is 130.

8.Identify all possible whole numbers with a square root between 2 & 3.
Answer:the square root of 2 is 4 & and the square root of 3 is 9. The whole numbers are 5,6,7,8.

### mussie mesgun scribe post

Questions 15-16

15. order the following numbers from the least to greatest: 7, SQRT 46, 5.8, SQRT 27, 6.3

A) SQRT 27 < 5.8 < 6.3 < SQRT 46 < 7

16. Fitness centre will install a square hot tub in a 6 m x 6 m room. They want the tub to fill no more than 75% of the room's area.

A) What is the maximum area of the hot tub?

Area of a square = LxL
= 6 m x 6 m
= 36 m^2

Area of the hot tub :(75/100)(36) = 27 m^2

B) What dimensions, to a tenth of a meter, will the fitness centre order from the manufacturer?
Explain.

They want the hot tub to fill no more than 75% of the room.

so 75% of the room is : (75/100)(36)= 27 m^2

The dimensions are SQRT 27 = 5.196m

L = 5.1 m
L = 5.1 m

## Tuesday, November 9, 2010

### Maya's Text Book Scribe Post

# 10 and 16.

Page 98
10) Kai uses an entire can of paint on a square backdrop for the school play. The label on the can states that one can covers 27m² of wall surface. Estimate the backdrop side length, to one decimal place.

Answer:
5.2 is the estimation of 27m².

Page 100
16) A tub in a fitness centre will install a square hot tub in a 6m × 6m room. They want the tub to fill no more than 75% of the room’s area.

a) What is the maximum area of the hot tub?

Answer:
The maximum area of the hot tub is 27m
²

b) What dimensions, to a tenth of a metre, will the fitness centre order from the manufacturer? Explain.

Answer:
The dimensions should be 5.1 by 5.1 so the area does not exceed 75% of the space available.

*Sorry if I didn't explain it well.

Here's a video to help you estimate square roots.

### Square roots

Question 2

Find a whole number that has a square root between 3 and 4 explain how your found it.

To identify the whole number that has a square root between 3 and 4 I found the perfect square of the two consecutive numbers and chose the whole number between the two perfect squares.

12 will have a value between 3 and 4
YOU KNOW THAT THIS IS YOUR ANSWER BECASUE 3 GROUPS OF 4 IS 12.
Question 3
Jason is doing his math homework he has to find the square root of 10.He presses 10 on his calculater and the screen display's 3.1627766. However when 3.1627766 is mutiplied by itself the answer is not 10, explain.
The answer is because 10 is not a perfect square the value shown on the calculator is only an approximation.

### Ana Lopena's Pythagoras Scribe Post

12. While shopping online, Jin Hun finds a square rug with an area of 11m2. He needs to know if it will fit in his 4m x 5m bedroom.

a) Estimate the side length of the rug to one decimal place.

b) Check your estimate with a calculator.

c) Will the rug fit? Explain.

Yes, because the side length of the room is 4m and 5m and the side length of the rug is 3.3m.

13. Stella is planning an outdoor wedding. She would like a square dance floor with an area of 115m2.

a) Determine the side length of the nearest tenth of a metre.

b) Stella finds out that the dance floor will be made up of 1m2. What are the two side lengths the dance floor can have that are the closest to what she wants?

10m x 10m or 11m x 11m

c)What are the two square areas for the dance floor that Stella can choose from?

100m2 or 121m2

d) Which area will Stella choose? Explain.

I think that Stella will choose 121m2 because it is closer to the area that she wanted.

### John's Pythagoras Scribe Post

Textbook Pages 98-100
#1 and 17

1.Explain how to estimate √28 to one decimal place without using a calculator.compare your answer with a classmate's

Answer:
To estimate √28 you have to find the two closest perfect squares. 25 and 36 are just right because 28 is between these two perfect squares. There are two method or ways to find the estimate of the square root of 28
The first one is a number line

HOW?
What I did was put the perfect squares on both ends of the number line and then I decided which is closest 28 which was 25 and I took a guesstimate and I got 5.3

Other way is this
HOW!?
The method is the same as the number line except you write it different. You just find what number 28 is closest to which is 25 and take a guesstimate that would be logical not over 5.5 since its closest to 25.

18.
a) Evaluate √9.
b) Estimate the square root of your answer
in part a), to one decimal place.
c) Use a calculator to check your estimate.
Express your answer to the nearest
hundredth.
d) How close is your estimate in part b)
to your calculation in part c)?

A)How to find the square root of 9? 9 is a perfect square so its easy, what I did was I looked for other perfect squares that are closest to 9 like 4 and 16 so 4 is 2x2 and 16 is 4x4 so 9 is 3x3 since its in the middle of 2 and 4
B)
C) The calculation is 1.73
D)My estimation in Part b was 0.2 larger than the actual calculation.

(HEY GUYS IF YOU FIND ANY MISTAKE, LEAVE A COMMENT AND PUT THE RIGHT ANSWER)