If the volume of a cone is 423.9 cubic inches with a height of 5 inches what is the radius

Vc  = (1/3) pi * r^2 * h    .....so

423.9 =(1/3)pi * r^2 * 5

423.9 = (5pi/3) * r^2      multiply both sides by ( 3 / [5 pi] )

80.959 = r^2      take the square root of each side

r = about 9 inches