We need to know where's the upper base and the lower base first. That's a triangular prism because the upper base and the lower base is in the form of a triangle. To find the lateral surface, don't look at the base, focus on other sides.
The other sides beside the bases is 3 lateral rectangles. To find the lateral surface area, add up the area of the 3 rectangles. lat sa = area of first rectangle + area of second rectangle + area of third rectangle lat sa = (13 × 2) + (12 × 2) + (5 × 2) lat sa = 26 + 24 + 10 lat sa = 60
