Question 3·Hard·Area and Volume

A right circular cone has a base area of $225\pi$ square centimeters and a vertical height of $20$ centimeters. A plane parallel to the base cuts off a smaller cone at the vertex. The volume of the smaller cone is $\frac{8}{125}$ of the volume of the original cone.

What is the total surface area, in square centimeters, of the remaining frustum?