Question

The base of regular triangular pyramid has sides that are 14 cm with a height of 12.1 cm. The slant height of the pyramid is 12.1 cm. What is the surface area of the pyramid?

A 254.1 cm2

B 338.8 cm2

C 423.5 cm2

D 508.2 cm2

Answer 1

To find the surface area, you need to find the area of the triangular base and the area of the 3 lateral faces.

All 4 of these are congruent based on the base and height measurements.

This means we will find the area of one and multiply it by 4.

A = 1/2bh
1/2 x 14 x 12.1
84.7 square cm

84.7 x 4 = 338.8 square cm

The answer is choice B.