A metal feeding trough is in the shape of a triangular prism with one of the faces missing. The base of the trough is an equilateral triangle with sides of length 3.5 feet and a height of 4 feet. If the trough is 15 feet long, how much metal was used to construct the trough?

Question

66.5 ft
119 ft
171.5 ft
194 ft

Answer 1

It sounds like the end sections are a triangle mounted by a rectangle. If so, then the ends each have area
4 * 3.5 + 3.5^2/4 √3

the sides are
two rectangles each 3.5*15
two rectangles each 4*15

so add up all the areas

If I got the shape wrong, it's because an equilateral triangle of side 3.5 cannot have a height of 4.