Answer:
it depends on what the question asks
Step-by-step explanation:
i think this is what you are asking for
volume = π x r^2 x h
diameter = 20, radius = 20/2 = 10
10^2 = 100
100 * 5 = 500
volume = 500π cubic cm
21/8*2= 5 2/8 or 5 1/4
Divide fraction so keep change flip
make them improper
21/8 * 2
42/8
5 2/8
5 1/4
