Pre-Cal/Algerbra Homework Question

Question

A rectangle is 3 inches longer than it is wide. 2 inch squares are cut out from each corner of the rectangle, and then the edges are raised to form a box. the volume of the box is 480. Find the dimensions of the original rectangle.

Answer 1

Volume of a rectangular prism:  V=lwh.

The width of this box will be x-4 and the length will be x-4+3 or x-1.  The height of the box when the edges are turned up will be 2.

 

If V=lwh, then 480=(x-1)(x-4)(2)

                      480=2(x²-5x+4)

                      240=x²-5x+4

                      x²-5x-236=0

 

Solve for x using the quadratic formula.