A cylinder with volume of and a radius of has its radius doubled. What is the volume of the new cylinder?

Rusty is considering making a cylindrical grain silo to store his crops. He has an area that is 6 feet long, 6 feet wide and 12 feet tall to build a cylinder in. What is the maximum volume of grain that he can store in this cylinder?

A cylinder has a height of 4 and a circumference of 16π. What is its volume