In a right triangle, the hypotenuse (the biggest side) is always bigger than the others. So we know the two sides are the ones touching the right angle. The area of a triangle is [tex]A_{tri}=\frac{1}{2}bh[/tex]
We know that [tex]A[/tex] is 18 and b and h must be the same since it's isosceles, so that means that really, it's [tex]b^{2}[/tex] instead of [tex]bh[/tex].
So:
[tex]18=\frac{1}{2}b^{2}[/tex]
Then solve for [tex]b[/tex]:
[tex]36=b^{2}[/tex]
[tex]b=6[/tex]
So the sides are both 6in.
