1, bicycle tripod;

2. Triangular room truss;

3, diagonal brace of rectangular door frame;

4. Triangular boom of crane;

5. Fixation of poles and towers of high-voltage transmission lines.

Characteristics of triangles:

Triangle has the characteristics of stability, firmness and compression resistance.

The reason is that each side of a triangle only faces an angle, and the length of the side determines the opening (that is, the size) of the angle. Think about it, any deformation with more than three sides.

One side corresponds to more than two angles. If more than two angles are determined by one side, as long as the sum of more than two angles remains unchanged, it can be distorted and deformed, so it is unstable. The conclusion is that triangles are the most stable.

Triangle is a closed figure composed of three line segments on the same plane but not on the same straight line, which has applications in mathematics and architecture.

Ordinary triangles are divided into ordinary triangles (three sides are unequal) and isosceles triangles (isosceles triangles with unequal waist and bottom and isosceles triangles with equal waist and bottom, that is, equilateral triangles); According to the angle, there are right triangle, acute triangle and obtuse triangle, among which acute triangle and obtuse triangle are collectively called oblique triangle.