(05.07 mc) mandy needs to paint all the faces and the base of a model pyramid she made for her history project. the dimensions of the pyramid are shown here. what is the total surface area of the pyramid? a square pyramid is shown. the side of the square is 10 inches. the height of the triangular faces is 9 inches.

To find the area of the square pyramid you will consider the shapes that make up the net of the pyramid (what it looks like when it is unfolded).

There are 4 congruent (same size and shape) triangles and a square.

The area of the square is
A = bh
     10 in x 10 in
A = 100 square inches.

The area of one triangle is
A = 1/2bh
    1/2 x 10 in x 9 in
A = 45 square inches

45 square inches x  4 (for the 4 triangles)

180 square inches of triangles

180 + 100 = 280

The total surface area of the square pyramid is 280 square inches.