Question

Find the radius of the cylinder with height 6 cm with volume 54 cubic cm

Answer 1

V = pi r^2 h
54 = 3.14 * r^2 * 6
54 = 18.84 r^2
Divide both sides by 18.84
r^2 = 2.866
Square root both sides
r = 1.7

Answer 2

The formula for volume of a cylinder is pi*r^2*h 

So reversing that, 

Volume/height/pi = 

54/6/3.14 = 2.86624203822 or 2.9