Surface area of a trangular prism with height of 15 a side with 9 and side with 12

A tip for doing these question, you should draw the shape out and label the sides, then calculate each side.
TSA (Total Surface Area) = 2(1/2*9*12) + 2(15*12) + 9*15
                                         = 108 + 360 + 135
                                         =603
Remember to add your units!