Can you help me with my math work?

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie

Someone answer this asap for the length, in feet, of a rectangular rug is represented by the expression 5x² + 2x. the width, in feet, is represented by the expression 3x². which expression represents the perimeter, in feet, of the rug? a. 8x² + 2x b. 8x² + 4x c. 16x² + 2x d. 16x² + 4x

Simplify this expression. 8x 16(x + y)