A tetrahedron is a four-faced polyhedron, or three-dimensional shape, created with triangles. The triangles in a tetrahedron are usually equilateral. To make a tetrahedron, you need paper, scissors, glue and an instrument, such as a protractor, to measure the sides and angles.
Plan and design your tetrahedron
The two most basic designs for a paper tetrahedron involve either a large equilateral triangle or a parallelogram. You will have to draw one of these shapes. For both, you will need to include foldable flaps on which you can add glue. An equilateral triangle has three equal sides that intersect at 60 degree angles, and one can be subdivided into four smaller equilateral triangles. If you choose the parallelogram method, you will need to draw a quadrilateral with one set of sides twice as long as the other. One set of opposite angles are 60 degrees each, but those in the other pair are 120 degrees each. Once again, four adjacent equilateral triangles will be created.
Cut out your shape
Cut out the shape, going around the glue flaps. If any of the edges are rough, you can fold those under one of the faces when you glue the figure together.
Fold and glue
Once your shape is cut out, fold the individual equilateral triangles toward one another to create the shape. Then, add a small amount of glue to the tops of each flap and slide it under the adjacent face. Let the glue dry to finish the tetrahedron.