A triangular prism is a three dimensional object. It has three square faces and two triangular faces. A triangular prism is different from a pyramid, which has either four triangular faces, or as is the case with the famous Pyramids of Giza, three triangular faces and one square face. Making a triangular prism out of paper is simple, though it requires some precision.
Draw a nine-inch by three-inch rectangle on the centre of a piece of paper. Divide this rectangle into three squares with three-inch sides.
Draw two equilateral triangles-one on each side of the middle square. An equilateral triangle has equal sides and angles. Use a protractor to measure the angle, which is always 60 degrees. All three sides of the triangles will be three inches.
Draw fold flaps on the three unused edges of each end square. You'll make six fold flaps all together. Make them one-half inch wide. They can be hand drawn as they will eventually be glued inside the prism.
Cut out the design. Make sure to cut exactly along the lines drawn, but only on the outside edge of the design.
Fold the paper on each remaining line, creasing it tightly to make a sharp fold. Fold all the flaps in an inward direction.
Lay the paper so that the middle square is on the bottom. Push the side squares and the triangles upward until their sides meet. This will form the shape of the prism.
Place a line of glue along each of the small fold flaps. Glue each flap to the inside of the triangle. The top two flaps will glue together. Let your prism dry.
If gluing the sides together is too fiddly all at once, glue one portion, let it dry, and then glue another portion.