To calculate the area of a pyramid, you need to calculate the area of each face and the base. To calculate the area of each face, you need to find the slant height. The area of each face is half of the length of the base times the slant height.

Square ABCD is its base.

V is the vertex.

Triangle VAB is a lateral face.

VA is a lateral edge.

h is the altitude.

l is the slant height.