Question 275311

SA of M is 2(3x5 + 5x7 + 3x7) = 2(15 + 35 + 21) = 2 x 71 = 142 sq units
By similarity, prism N is 3 times prism M, so the surface area is 3 x 3 times the surface area of prism M.. The SA of N is thus 9 x 142 = 1278