You have a triangular prism on top of a rectangular prism. The surface area is the sum of the areas of the exposed faces.
Starting with the triangular prism, the surface area is the area of the two triangular bases plus the area of the two rectangular sides (the bottom rectangular face is ignored).
A = ½ (10) (12) + ½ (10) (12) + (13) (9) + (13) (9)
A = 60 + 60 + 117 + 117
A = 354
The surface area of the rectangular prism is the area of the two rectangular bases (front and back), plus the two walls (left and right), plus the bottom, plus the top (minus the intersection with the top prism).
Its an easy one first thing you look at is the -(5), if u looked closely their is a - sign in front of the 5 its a -1 do if you multiply the -1 to 5 so it will be -5 and then multiply -5 ,3 time it will be positive 125 because u multiply the -5 , 3 times. I hope that helped a lott. :)
1. Break into triangles, then add. In the figure<span> on the right, the </span>polygon<span> can be broken up into triangles by drawing all the diagonals from one of the vertices. If you know enough sides and angles to </span>find the area<span> of each, then you can simply add them up to </span>find<span> the total.</span>