Suppose that n is the input variable.
First, find the range for the loop. As stated in the problem, you will have to print the radius and volume n times. Hence, you will get the range (1,n+1).
for r in range (1,n+1):
Note: The variable r is equal to the radius. Therefore, if you want to print the radius, print r.
Second, find the calculation for the volume and put it in the loop.
The final step is the print statement, make sure to put it in the loop.