Answer:
B. 18 sq in.
Step-by-step explanation:
Surface area of the triangular pyramid excluding the base = area of the three triangular faces = 3(½ × base × height)
Where,
base = 3 inches
height = ED = 4 inches
Plug in the known values into the equation
Surface area of the triangular pyramid excluding the base = 3(½ × 3 × 4)
= 3(3 × 2)
= 3(6)
= 18 sq in.
