Find the total surface area of the square pyramid. the base (bottom) has an area of 36 square centimeters. one triangular face (side) has an area of 27 square centimeters.

So we know a pyramid has 4 triangles and 1 square
All the triangles are equal, so this means that we need to do our area of the side times 4 to know the total above ground area of the pyramid.

4x27 = 108 cm²
Now the bottom is given so we just add the number to the others:
108+36= 144 cm²

The expressions would be 0.25a

The answer would be (c)