## Thursday, January 27, 2011

### Breanna's Homework Book Pg.54-55

These are the 3 questions I did in our homework booklet.
Question #2

Calculate the serface are of each rectangular prism to the nearest tenth of a centimetre squared.
a)
LxW
11.5 x 3.2 = 36.8
11.5 x 3.2 = 36.8
11.5 x 5 = 57.5
11.5 x 5 = 57.5
3.2 x 5 = 16
3.2 x 5 = 16

36.8 + 57.5 + 16 = 110.3
110.3 x 2 = 220.6
T.S.A = 220.6

b)
LxW
12 x 10.4 = 124.8
12 x 10.4 = 124.8
12 x 4.5 = 54
12 x 4.5 = 54
10.4 x 4.5 = 46.8
10.4 x 4.5 = 46.8
124.8 + 54 + 46.8 = 225.6
225.6 x 2 = 451.2
T.S.A = 451.2
Question #3
Find the surface area of each triangular prism to the nearest tenth of a centimetre squared.
a)
LxW/2 LxW
7 x 2.5 = 17.5
8 x 2.5 = 20
10.6 x 2.5 = 26.5
8 x 7 = 56 /2 = 28
8 x 7 = 56 /2 = 28
17.5 + 20 + 26.5 + 28 +28 = 120
T.S.A = 120 cm squared.

b)

L x W/2 L x W
8 x 4.5 = 36
8 x 4.5 = 36
8 x 4.5 = 36
3.35 x 6 = 20.1 /2 = 10.05
3.35 x 6 = 20.1 /2 = 10.05
36 + 36 + 36 + 10.05 + 10.05 =128.1
T.S.A = 128.1

Question #4

Ty is painting this storage bench for the deck. How much area does he need to paint, to the nearest hundreth of a square metre?
LxW
0.5 x 1.56 = 0.78
0.5 x 1.56 = 0.78
0.5 x 1.56 = 0.78
0.5 x 1.56 = 0.78
0.5 x 0.38 = 0.19
0.5 x 0.38 = 0.19
0.78 x 4 = 3.12
0.19 x 2 = 0.38
0.38 + 3.12 =
T.S.A = _______
Here is a link that I found! *click here*
Also Here`s a video I found! Check it out

What is the answer to question #4?

#### 1 comment:

1. Good job Breanna. I liked the video you chose to include in your post. I realized for the area of a triangle you had LxW/2 but it is bxh/2. Great job!