Please answer me Q#32 page#104 from the following link https://tstuition.wikispaces.com/file/view/3+-+Mensuration.pdf many many thanks

A bucket in the shape of a frustum has an upper diameter
of 10 cm and a lower diameter of 4 cm.  The frustum has a height of 3
cm.

The formula for the volume of a frustum
is...

V = [h(B2 - B1)] / 3   where h represents the height,
B2 is the area of the larger base, and B1 is the area of the smaller
base.

First, lets find the area of the two
bases.

Larger base (B2):  A = pi * r^2 = pi * 5^2 = pi * 25
= 25`pi`

Smaller base (B1):  A = pi * r^2 = pi * 2^2 = pi *
4 = 4`pi`

Remember, you must use radius instead of
diameter.  Thats why 10 changed to 5 and 4 changed to
2.

Now we use this in our volume
formula.

V=[h(B2-B1)]/3

[3(25`pi`
- 4`pi` )] / 3

(3 * 21`pi` ) / 3     (the 3s will
cancel)

The volume of the frustum is 21`pi` cubic
cm