Question

A wooden building has the shape of a

rectangular pyramid. The building's
base is 100 meters long and 50
meters wide. The height of each
triangular face is 40 meters. How
much wood was used to make the
entire building?
A 33,000 m²
B 13,000 m2
C 11,000 m2
D 6,000 m2

Answer 1

B: 13000 m²

Explanation:

To find how much wood is used, we will have to find the surface area of the wooden building.

Formula for surface area of a rectangular pyramid is;

SA = lw + l√(h² + w²/4) + w√(h² + l²/4)

We are given;

l = 100 m

w = 50 m

h = 40 m

Thus;

SA = (100 × 50) + 100√(40² + 50²/4) + 50√(40² + 100²/4)

SA = 5000 + 4717 + 3201.56

SA = 12918.56

Approximating to 2 significant figures gives;

SA = 13000 m²