## Thursday, January 27, 2011

### Homework Book Pg 54-55

Choose 3 questions from pages 54 and 55

2. Calculate the surface area of each rectangular
prism to the nearest tenth of a centimeter squared.

length x width = a
S- 5 x 3.2 = 16 cm2
- 5 x 3.2 = 16 cm2
F- 11.5 x 5 = 57.5 cm2
- 11.5 x 5 = 57.5 cm2
T- 11.5 x 3.2 = 36.8 cm2
- 11.5 x 3.2 = 36.8 cm2
________________________________
Total Surface Area =220.6 cm2

length x width = a
F- 12 x 10.4 = 124.8 cm2
- 12 x 10.4 = 124.8 cm2
T- 10.4 x 4.5 = 46.8 cm2
- 10.4 x 4.5 = 46.8 cm2
S- 12 x 4.5 = 54 cm2
- 12 x 4.5 = 54 cm2
________________________
Total Surface Area = 451.2 cm2

3. Find the surface area of each triangular
prism to the nearest tenth of a meter squared.

a of a triangle = base x height divided by 2
a of rectangle = length x width
8 x 2.5 = 20 m2
10.6 x 2.5 = 26.5 m2
2.5 x 7m = 17.5 m2
7 x 8 = 56/2 = 28 m2
7 x 8 = 56/2 = 28 m2
___________________
Total Surface Area = 120 m2

a of a triangle = base x height divided by 2
a of rectangle = length x width
8 x 4.5 = 36 m2
8 x 4.5 = 36 m2
8 x 6 = 48 m2
6 x 3.35 = 20.1/2 = 10.5
6 x 3.35 = 20.1/2 = 10.5
_____________________
Total Surface Area = 140.1 m2

4. Ty is painting this storage bench for the deck.
How much area does he need to paint, to the nearest
hundredth of a square meter?

length x width = a
S- 0.38 x 0.5 = 0.19 m2
- 0.38 x 0.5 = 0.19 m2
F- 0.5 x 1.56 = 0.78 m2
- 0.5 x 1.56 = 0.78 m2
T- 1.56 x 0.38 = 0.5928 m2
- 1.56 x 0.38 = 0.5928 m2
________________________
= 3.1256 round up...
Total Surface Area = 3.13 m2

Cylinder Volume and Volume Problems

r = d / 2…………………….v = π.r.r.h asdfghjkl;………….502.4m3^ / 2 = 251.2m3^
r = 8 /2……………………..v = (3.14 x 4 x 4) x 10
r = 4m……………………….v = 50.24 m2^ x 10m
…….asdfghjkl;…………….v = 502.4 m3^

r = d / 2.......................v = π.r.r.h
r = 80 / 2……………….v = (3.14 x 40 x 40) x 45
r = 40cm……..….……..v = 5024 cm2^ x 45cm
……………………………..v = 226,080cm3^

226,080 / 80 = 2826cm2^
2826 / 3.14 = 900cm
√900 = 30cm
30 x 2 = 60cm -diameter