jmc

The area of a triangle is shown by $\frac{1}{2}bh$. We set the base equal to $24$, and the area equal to $60$, and we get the height, or altitude, of the triangle to be $5$. In this isosceles triangle, the height bisects the base, so by using the Pythagorean Theorem, $a^2+b^2=c^2$, we can solve for one of the legs of the triangle (it will be the the hypotenuse, $c$). $a=12$, $b=5$, $c=13$. The answer is $\boxed{13}$