Question

If a square pyramid of base 12 cm and height 5 cm is to be made, then its triangular faces are all equilateral triangles with side 12 cm.

• A. 110
• B. 100

Answer 1

The correct option is B

100

The base of the triangular faces measures the same as the side of the square pyramid which is side 12 cm.

However, the slant height of the triangle is calculated to be

$\sqrt{6^2+5^2}=\sqrt{61}$.

If the triangular faces are equilateral triangles of side 12 cm, then slant height = $\sqrt{{12}^2-6^2}=\sqrt{108}$.

Hence, the triangular faces are not equilateral triangles of side 12 cm.