The volume of a cylinder is the product between the base area and the height.
The base area is
, where the radius is half the diameter:

Multiply this number by the height and you have the volume:

27 times 27
7 times 2,401
1,000,000,000 divided by 10,000,000
390,625 divided by 5
hope this helps!!
check the picture below.
notice, by drawing the altitude from C, we end up with a 30-60-90 and a 45-45-90 triangle, thus we use the 30-60-90 and 45-45-90 rules as you see there.

2 quarters, 3 dimes and 4 nickels
162.56cm or if you round it, 163cm