Find the lateral surface area of a pyramid whose base is an equilateral triangle. The slant height is 14 ft, and the length of each side of the triangular base is 6 ft.

[tex]\[
LSA = [?] \text{ ft}^2
\][/tex]



Answer :

To find the lateral surface area (LSA) of a pyramid with a base that is an equilateral triangle, follow these steps:

1. Identify the given values:
- Slant height (l) of the pyramid: 14 feet
- Side length (a) of the equilateral triangle base: 6 feet

2. Determine the perimeter of the base:
- Since the base is an equilateral triangle, all three sides have the same length.
- Therefore, the perimeter of the base (P) is calculated as follows:
[tex]\[ P = 3 \times a \][/tex]
Substituting the given side length:
[tex]\[ P = 3 \times 6 = 18 \text{ feet} \][/tex]

3. Calculate the lateral surface area (LSA):
- The formula to find the lateral surface area of a pyramid is:
[tex]\[ \text{LSA} = \frac{P \times l}{2} \][/tex]
Where [tex]\( P \)[/tex] is the perimeter of the base and [tex]\( l \)[/tex] is the slant height.

Substituting the values we have:
[tex]\[ \text{LSA} = \frac{18 \times 14}{2} \][/tex]

4. Simplify the calculation:
[tex]\[ \text{LSA} = \frac{252}{2} = 126 \text{ square feet} \][/tex]

Thus, the lateral surface area of the pyramid is [tex]\(126 \text{ ft}^2\)[/tex].