Answer:
21.9 mm^2
Step-by-step explanation:
A triangular prism has 4 sides, 3 on the top and 1 on the bottom.
To calculate the area of the top 3, we can use the formula area = base * height/2. Each triangle of the top 3 has a base of 3 and height of 4, so the total surface area for the top 3 triangles is 3 * (3*4/2) = 18 mm^2
For the bottom triangle, it has a base of 3 and height of 2.6, so its area is (3*2.6/2) = 3.9 mm^2. Add these two up to get 21.9 mm^2 as our answer
