## Wednesday, February 16, 2011

### Diana's Homework Book Post.

Even numbers, Pages 78-79.

4. A)

B)

C)

6. A)

Both rectangular prisms have the volume of 200cm.

B)

Both rectangular prisms have the volume of 10.5 m3.

8.

The need to put 24.3m3 of water in the pool.

Comment if I did anything wrong.
Also , sorry that a couple of my pictures are not the right way they wouldn't want to rotate.

Chapter 7.3

Jumbo:
r= d÷2 V=(pi.r.r)x h
r= 20÷2 V=(3.14x10x10)x40
r=10cm V=314 x 40
V=12'560cm³

Popcorn Lover's:
r= d÷2 V=(pi.r.r)x h
r= 30÷2 V=(3.14x15x15)x20
r= 15cm V= 7065 x 20
V= 14'130cm³

Martha should buy the popcorn lover's one because it has a greater volume than the Jumbo one.Popcorn Lover's volume is 14,130cm³ and Jumbo's 12,560cm³.

Chapter 7.4

Outside;
r=d÷2 V=(pi.r.r)x h
r= 1÷2 V=(3.14x0.5x0.5)x10
r=0.5m V= 0.785 x 10
V= 7.85m³

Inside;
r= d÷2 V=(pi.r.r)x h
r= 0.8÷ 2 V=(3.14x0.4x0.4)x10
r= 0.4m V=0.5024 x 10
V= 5.024m³

You Subtract the volume of the inside from the volume of the outside.
7.85m³ - 5.024m³ = 2.826m³

The volume of concrete needed to make the culvert is 2.826m³