The legs of a right triangular prism measure 9 inches and 12 inches. The prism has a height of 5 inches. What is the surface area of the prism?

Answer 1

the two bases have area 9*12/2 = 54
the three lateral faces are rectangles, with height 5, and width equal to the sides of the right triangle.

So now you just have to determine the hypotenuse of a scaled-up 3-4-5 right triangle (or use the Pythagorean Theorem, if you must).

Answer 2

thank you so much oobleck for your help!