Chapter 2, Problem 31P

The perimeter of an rectangle shown in Fig. P2.31 is given by

$P=2\left(\frac{A}{L}+L\right)$ If the perimeter P 30 m and the area $A=W\times L=36{\text{m}}^2$, find the length L,

and width w as follows:

(a) Substitute the values of P and A in equation (2.74) and obtain the quadratic equation for L.

(b) Solve the quadratic equation for L obtained in part (a) by completing the square, and the quadratic formula. Also, compute the corresponding values of W.