80π/3 or about 83.775
since a cone is 1/3 of a cylinder, we need to find the base's area. since area = πr^2, we get 16π. then, multiplying this by 5, we get 80π. dividing by 3, since the cone's volume is 1/3 of that of a cylinder's, we get 80π/3.
hope this !
just multiply it
use distributive property on all like terms and change your signs if you have a double negative or if you have positive/negative