How can I find the volume with out giving me the width?

Question

A square based pyramid has a height of 7 feet and the edge length of the base is 4 feet. A second square based pyramid is 2 feet taller and the edge length of the base is 0.5 feet greater than the first pyramid. How much greater is the volume of the second pyramid than the volume of the first pyramid? Round your answer to the nearest hundredth.

Answer 1

In a  square, all sides are equal (length=width)

V = 1/3 BH     V = 1/3 s² H

V = 1/3(4²)(7) = 112/3 = 37.3333

V = 1/3(.5)²(9) = .75

.75 - 37.3333 = 36.6 feet³