Question

Please help me find the surface area of the triangular prism ( number 3)

Answer 1

Check the picture below.

so the triangular prism is really 3 rectangles and two triangles stacked up to each other at the edges, so if we simply get the area of each figure individually and sum them up, that's the area of the prism.

let's notice, the triangles have a base of 2.4 and a height/altitude of 1.

$\bf \stackrel{\textit{2 triangles's area}}{2\left[ \cfrac{1}{2}(2.4)(1) \right]}~~+~~\stackrel{\textit{right rectangle}}{(2\cdot 1.5)}~~+~~\stackrel{\textit{left rectangle}}{(2\cdot 1.7)}~~+~~\stackrel{\textit{bottom rectangle}}{(2\cdot 2.4)} \\\\\\ 2.4+3+3.4+4.8\implies 5.4+8.2\implies 13.6$