Volume of sphere = Volume of cylinder
4/3 * PI * R**3 = PI * R**2 * H
substituting 3 for H and dividing both sides of equation by PI:
4/3 * R**3 = 3 * R**2
Multiplying both sides by 3/4:
R**3 = 9/4 * R**2
Dividing both sides by R**2:
R = 9/4 = 2.25
Verification
Volume of sphere = 4/3 * PI * R**3 = 4/3 * 3.14 * 2.25 **3 = 47.7
Volume of cylinder = PI ** R**2 * H = 3.14 * 2.25**2 * 3 = 47.7