Answer:
105in²
Explanation:
Surface area is the total area of the faces.
The faces of pyramid consist of triangles and a square
The area of a square can easily be calculated by squaring the side length
the square of this pyramid has a side length of 5
so
area of square = 5²
5² = 25
the area of the square is 25in²
Now to find the area of the triangles
All we have to do is find the area of one triangle and multiply that buy 4 ( because there are four triangle)
the area of a triangle can be calculated using this formula :
where b = base and h = height
The triangles have a base length of 5 in and a height of 8 in
so

So the area of one triangle is 20 in²
Now we multiply 20 by 4 to find the area of all 4 triangles
20 * 4 = 80
So the total area of the triangles is 80in²
Finally we add the two areas together
Surface area = 80 + 25
80 + 25 = 105
Hence, the surface area is 105in²