## Wednesday, February 16, 2011

### Homework Book Pages 4, 6, and 8

a= l x w
a= 15 x 12
a= 180cm²

v= area of base x height
v= 180cm² x 3cm
v= 540cm³

a= l x w
a= 8.5 x 7
a= 59.5cm²

v= area of base x height
v= 59.5m² x 2m
v= 119m³

a= l x w
a= 20 x 8
a= 160cm²

v= area of base x height
v= 160cm² x 16cm
v= 2560cm³

v= b x h/2 x h²
7.2 x 4.5/2 = 32.4cm²
v= 32.4cm² x 10cm
v= 324cm³

v= b x h/2 x h²
3 x 5/2 = 7.5m²
v= 7.5m² x 8.5m
v= 63.75m³

c) A prism where the base of the triangle is 4m, the height of the triangle is 5m, and the prism height is 12m.

v= b x h/2 x h²
4 x 5/2 = 10m²
v= 10m² x 12m
v= 120m³

Pear juice:

a= l x w
a= 9 x 6
a= 54cm²

v= area of base x height
v= 54cm² x 4.5cm
v= 243cm³

Pineapple juice:

a= l x w
a= 10 x 6
a= 60cm²

v= area of base x height
v= 60cm² x 3.75cm
v= 225cm³

The second juice box holds more.

This tells you how to find the volume of a rectangular prism.

Cylinder Volume and Volume Problems

d/2= r
8/2= r
4m= r

V= π x r x r x h
V= (3.14 x 4 x 4) x 10
V= 50.24m^2 x 10m
V= 502.4m^3

502.4m^3/2 = 251.2m^3The volume of the semicircular trough is 251.2m^3.

Outside:
d/2= r
1/2= r
0.5m= r

V= π x r x r x h
V= (3.14 x 0.5 x 0.5) x 10
V= 0.785m^2 x 10m
V= 7.85m^3

Inside:
d/2= r
0.8/2= r
0.4m= r

V= π x r x r x h
V= (3.14 x 0.4 x 0.4) x 10
V= 0.5024m^2 x 10m
V= 5.024m^3

7.85m^3 - 5.024m^3 = 2.8m^3