Answer:
72 in²
Step-by-step explanation:
since the trap is open left and right, we don't include these side areas.
so, all we have for the surface area are
the top rectangle (2.5 in × 12 in),
the bottom rectangle (2 in × 12 in)
the back rectangle (1.5 in × 12 in)
for the total surface area we need to to add all 3 areas up.
in our case we get
2.5 × 12 = 30 in²
2 × 12 = 24 in²
1.5 × 12 = 18 in²
total is then
30 + 24 + 18 = 72 in²
