To make a four-sided pyramid out of cardboard, simply attach four triangles to the sides of a square, and then fold the triangles up and secure them at the apex. Lay all the pieces out and tape them together, and fold them together as the final step.
A four-sided pyramid is a tangible example of a three-dimensional geometric shape. It is easy to make a model with a piece of sturdy cardboard, a pencil, ruler, scissors and some tape.
Step 1: Draw the pieces
Use a ruler and a pencil to draw four equivalent triangles. Draw a square with sides equal to the measure of the base of the triangles.
Step 2: Cut out the pieces
Use a pair of sharp scissors to cut the five pieces out of the cardboard. If the cardboard is too thick for scissors, a craft knife works well.
Step 3: Tape the pieces together
Lay out the triangle pieces and tape the sides together. The end result will resemble an incomplete circle. Tape one side of the square to the base of one of the triangles.
Step 4: Complete the pyramid
Fold the triangle together and join the two remaining sides with a piece of tape. The figure now resembles a four-sided pyramid. Fold the square piece up and tape it to the remaining three bottom edges of the pyramid to complete the figure.