Advice 1: How to make a tetrahedron

To make the tetrahedron, we need to take a sheet of paper, scissors and glue. You then cut out a paper scan of a tetrahedron and glue. If there are 4 sheets of colored paper, the tetrahedron will be even more beautiful.
You will need
  • a sheet of paper, scissors, glue
To make the tetrahedron, we must take a sheet of heavy paper or cardboard and draw on it shown in the drawing scan. Scan size can be arbitrary. Not necessarily to copy is presented in the figure figure. In fact, the scan consists of four equilateral, equal, triangles (not counting suitable for gluing the petals).
Then you need a pair of scissors carefully cut the drawn on paper scan it and bend it on all lines. To place bend is smooth and clear, you can use any metal object. For example, the handles of the scissors. If the workpiece is cut out of cardboard or thick, quite heavy paper, the fold lines must be cut with something very sharp such as a razor blade.
After this "pattern" you have to join. Petals for gluing of faces should be placed inside the formed shape. If the cardboard was made the incisions, they should be outside of the tetrahedron.
The tetrahedron is the simplest figure among all polyhedra. It consists of only four faces — equilateral triangles. Four faces are the minimal number of edges that separates the closed part of the space. The tetrahedron has many properties of regular polyhedra. All of his faces - regular (equilateral) polygons (triangles), and each of them is separated by an edge from exactly one face. All the angles of the tetrahedron are equal.
Useful advice
So the tetrahedron has become colored, you can paint each face of the figure in a different color. Colored tetrahedron can be obtained using the sweep cut from different sheets of colored paper. Thus it is necessary to prepare four basic sweep – each in the form of an equilateral triangle. Gluing colored tetrahedron is similar to a simple (single color) figure.

Advice 2 : How to make a pyramid out of cardboard

Shapes and structures in the form of pyramids there are in every culture and since ancient times people knew about that pyramid shape have a special power and affect the life and health of people. Today, with the help of the figures in the form of pyramids can home to experiment with the energy field of the food, water, and even try to treat diseases using own little pyramid. Of the available materials you can make a simple cardboard pyramid in the proportions of "Golden section".
How to make a pyramid out of cardboard
The primary value in the pyramid, built on the Golden section, is 7, 23 see Also you need to know the ratio of the Golden section, which is being studied in schools on the lessons of geometry – it is equal to 1,618.
Multiply by by 72.3 1,618 – you will get the result that you want to round to the nearest whole number in millimeters. This number will be the length of the base of the pyramid (117 mm). The height of the pyramid will be 72 mm.
Calculate the size of the triangular faces of the pyramid, using all known the Pythagorean theorem. Following settlement you will receive all sizes for manufacturing of model of a pyramid – the base of the pyramid will have a length of 117 mm, its height is 93 mm. If you don't want to have an empty pyramid, and want to do for her bottom, multiply 117 by 117, to form a square base.
According to the calculations, draw on cardboard, plywood, plastic or other material selected for bonding of the pyramid, all the details. Cut parts of a pyramid of cardboard with sharp scissors – you get four of the same triangle.
All of the triangle parts spread out on a flat surface, and connect them to the brink. Edges of adjacent triangles temporarily connect masking tape. Adding the last triangle, assemble the parts, raising the model in the vertical plane.
Neat stitching edge, achieving maximum clarity. The angles of the triangles should ideally be aligned at the top, and the corners should be aligned on the base. Glued right pyramid obtained accurate and stable.
The seams of the pyramid from the inside cover with adhesive. It's enough if you decided to make a hollow pyramid. If the pyramid is planned the bottom, it needs to be glued separately, at the end of the entire work.
Remove the auxiliary tape from the seams of the pyramid, and then set up her own energy to the pyramid worked in your favor.
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