1. simplify. 75a^2/5
2. find altitude of the triangle with 13,13 and the base of 10.
75/5 = 15
so
15 a^2
5 12 13 is a right triangle (one of those you memorize like 3 4 5)
25 + 144 = 169
half the base is 5
altitude is 12 because hypotenuse is 13
so
(1/2) b h = 5*12 = 60