Answer:
SA = 1,176 ft².
Explanation:
To find the surface area of the triangular prism, we can solve for the rectangular base, both triangular faces, and lateral sides separately.
For the rectangular base: (Use formula l×w)
20 × 18 = 360 ft²
For the triangular faces: (Use formula 1/2(b·h)
1/2(18 × 12) = 108 ft²
Since there are two faces, we need to double the amount.
108 × 2 = 216 ft².
Finally, solve for the lateral sides:
20 × 15 = 300 ft².
There are two sides, so:
300 × 2 = 600 ft².
Add up all of these areas:
600 + 216 + 360 = 1,176 ft²