+128475 We have a triangle that makes up the bottom of the figure with a base of 13 and an altitude of 11.3
Its area is (1/2)(13)(11.3) = 73.45 cm^2
Then we have three congruent triangles making up the sides with bases of 13 and heights of 9
Their combined area is 3 (1/2) ( 13) (9) =175.5 cm^2
So....the total surface area = 73.45 + 175.5 = 248.95 cm^2
