Textbook: Page 34 #14

14) A chimney has the dimensions shown. What is the outside surface area of the chimney? Give your answer to the nearest hundredth of a square metre. 

Lables:

r1 & h1= big cylinder

r2 & h2= small cylinder

SA= 2π(r1xh1) + 2π(r2xh2) + [πr2^2 - πr1^2]

SA= 2π(25)(90) + 2π (15)(40) + [π(25)^2 - π(15)^2]

SA= 14137.17cm^2 + 3769.91cm^2 + [1963.50 - 706.86]

SA=  14137.17cm^2 + 3769.91cm^2 + 1256.64cm^2

SA= 19163.71cm^2

Conversion:

1963.71cm^2 x 1m^2/10000cm^2=1.92m^2

Answer: 1.92m^2

Textbook Page 79 #20

20. Leon's rectangular living room is 8.2 m by the 4.5 m. A square rug covers 2/5 of the area of the floor. What is the side length of the rug, to the nearest tenth of a metre.

I first find the area of the living room.

A=  l x w
A = 8.2 (4.5)
A= 36.9

Then, I find 40% of the area of the living room (36.9m). I got 40% because 2/5 is equivalent to 40%. 40% of the area of the living room is 14.7. I got to this answer by:

0.40 x 36.9= 14.7

I then find the side length of the rug by getting the square root of 14.7 which equals 3.82.

A= l x w
√14.7 = 3.82

The side length of the rug is 3.82 m.

Textbook: Page 61 Question 18

18. Determine the mean of each set of numbers. Express your answer to the nearest hundredth, if necessary.

a) 0, -4.5, -8.2, 0.4, -7.6, 3.5, -0.2

To determine the mean, I first add all the numbers together:
0 + -4.5 + -8.2 + 0.4 + -7.6 + 3.5 + -0.2= -16.6

I then divide the sum with how many numbers I used to add it with.

-16.6/7= -2.37

b) 6.3, -2.2, 14.9, -4.8, -5.3, 1.6


6.3 + -2.2 + 14.9 + -4.8 + -5.3 + 1.6= 10.5

10.5/6= 1.75