The sides of a triangle are its 15 cm and 17 cm its area is

In a column proof the right column states your reasons

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.

He trapezoid is composed of a rectangle and two triangles. what is the area of the rectangle? what is the total area of the triangles? what is the area of the trapezoid? ? a) 42 cm2; 27 cm2; 69 cm 2 b) 54 cm2; 27 cm2; 81 cm 2 c) 108 cm2; 27 cm2; 135 cm 2 d) 108 cm2; 13.5 cm2; 121.5 cm 2