Since this is a right triangle, we can use the Pythagorean theorem to find the hypotenuse of length 'c'.
[tex](length-of-leg1)^2+(length-of-leg2)^2=(length-of-hypotenuse)^2\\15^2+36^2 =c^2\\c = \sqrt{15^2+36^2} \\c= 39[/tex]
Thus c equals 39.
Hope that helped!
