in right triangle abc , ac is the hypotenuse . if ac is 10 and ab + bc = 20 , what is the area of the triangle abc ?
"square ab + bc = 20 : ( ab ) ^ 2 + 2 * ab * bc + ( bc ) ^ 2 = 400 . since ( ac ) ^ 2 = ( ab ) ^ 2 + ( bc ) ^ 2 = 10 ^ 2 = 100 , then ( ab ) ^ 2 + 2 * ab * bc + ( bc ) ^ 2 = 100 + 2 * ab * bc = 400 . 100 + 2 * ab * bc = 400 . ab * bc = 150 . the area = 1 / 2 * ab * bc = 75 . answer : c ."
triangle_area_three_edges(10, multiply(const_3, const_10), multiply(const_4, const_10))