Answer:
The answer is option A
Explanation:
Surface area of a pyramid =
area of base + area of triangular faces
Since it's a square based pyramid
It's surface area is
area of base + 4( area of one triangular face)
Since the square has equal sides
For square base
Area of a square = l²
where l is the length
From the question l = 5
So we have
Area of square base = 5² = 25ft²
For one of the triangular face
Area of a triangle = ½ × base × height
base = 5
height = 6
Area = ½ × 5 × 6 = 15ft²
So the surface area of the pyramid is
25 + 4(15)
= 25 + 60
We have the final answer as
Surface area = 85 ft²
Hope this helps you