V=4/3πr^3 with 5 inches radius

Write "5" in place of 'r' in the volume formula:

V = 4/3 π (5) ³

V = (4/3 π) (125)

Then just crank through the numbers, using a pencil or a calculator.

' 3.14 ' is usually a sufficiently precise value to use for π.

You know π=22/7=3.14

v=⁴/3 •π•r³

v=⁴/3•3.14•5³

v=4/3•392.5

v=1570/3

v=523.33