The surface area is the sum of the areas of all sides.
area of two triangle end pieces:
(1/2)(9)(15) + (1/2)(9)(15) = 135
area of front rectangle piece:
(17.4)(16) = 278.4
area of bottom rectangle:
(15)(16) = 240
area of back rectangle:
(9)(16) = 144
Total surface area:
135 + 278.4 + 240 + 144 = 797.4 m²
