What is the diameter of a cone that has a volume of 56.52 cubic inches and a height of 6 inches. use 3.14 for pi\

The volume of a cone is 1/3*(pie)*r^2*h
56.52=1/3*(pie)*r^2*6
Then divided 1/3 and pie to both side 
56.52/1/3*pie=r^2*6 
59.19=r^2*6
59.19/6=r^2 
9.86=r^2
then square root the r 
 r=3.14 
d=3.14*2
answer= 6.28