Answer
88.2
Work Step by Step
$90^2+x^2=126^2$
$8100+x^2=15876$
$x^2=7776$
$x=\sqrt {7776}$
$\sqrt {7776}\approx 80$
Divide and find the average to approximate the solution.
$7776/div80=97.2$
$(80+97.2)\div2=88.6$
Repeat to further refine.
$7776\div88.6=87.77$
$(88.6+87.77)\div2=88.19$
