Chapter 11 - Section 11.2 - Solving Quadratic Equations by Completing the Square - Exercise Set - Page 777: 57

Length: 70.71 meters Area: 5000 $m^2$

Square pen must be 100 meters on the diagonal $x^2+x^2=100^2$ $2x^2=10000$ $2x^2/2=10000/2$ $x^2=5000$ $\sqrt {x^2} = \sqrt {5000}$ $x =± \sqrt {5000}$ $x = ± 70.71$ We want a length, so we ignore $-70.71$ as an answer. The sidelength of one side is 70.71 meters. $A=s^2$ $A = 70.71^2$ $A =5000$