Question

What is the surface area of the regular pyramid below?

Answer 1

648 square units.

EXPLANATION

The surface area of the regular pyramid is the area of the base plus the area of the 4 triangular faces.

We use the formula;

`S.A = {l}^(2) + 4 * (1)/(2) bh`

where l=12 units is the length of the square base and h=21 units is the vertical height of the triangular faces.

We substitute the values to get;

`S.A = 12^(2) + 4 * (1)/(2) * 12 * 21`

`S.A = 144+ 504`

`S.A =648 {units}^(2)`

Answer 2

648 sq units

Explanation:

Area of the base= 12×12= 144 sq. units

Perimeter of the base=4×12= 48

Total surface area= 1/2×48×21 + 144

=648 sq units