Answer:
756 cm^2
Step-by-step explanation:
9 x 12 = 108 triangles
9 x 18 = 162 back side
9^2 + 12^2 = c^2
9^2 + 12^2 = 225
9^2 + 12^2 = 15^2
length of the hypotenuse is 15 so
15 x 18 = 270 slanted top
18 x 12 = 216 bottom
216 + 270 + 162 + 108 = 756 cm^2
