Answer
base = 16 miles, height = 6 miles
Work Step by Step
$a=b*h$
$96 = (x+5)(x-5)$
$96 = x^2+5x-5x-25$
$96 = x^2-25$
$121 = x^2$
$\sqrt {121} = \sqrt {x^2}$
$x = ± 11$ ($x\ne-11$ since we can't have a negative side length. Thus, $x=11$)
$(x+5)(x-5)$
$(11+5)(11-5)$
$16*6$
