Answer:
a.
b.
c. They are equivalent
Step-by-step explanation:
a. The trapezoid can be divided into two triangles and one rectangle. For the three figures, the height is 12ft. For the rectangle, the dimensions are 12ftx10ft. Since the legs are of the same length the triangles have a base of 9ft (because the rectangle takes 10 feet from the base of 28 feet and there are 18 feet left over, these 18 are divided equally between the two triangles).
b. The formula is
c. They are equivalent