The content of the Mathematics Dragon Boat Festival handwritten newspaper is as follows: 1. Zongzi is an indispensable traditional delicacy during the Dragon Boat Festival. Chinese rice dumplings not only have rich and diverse fillings, but also come in various shapes, including bamboo tube, rectangle, cone, pyramid, triangle, etc.

But the most common one is the "four-corner zongzi", which is a triangular tetrahedral zongzi. Why are the zongzi triangular?

2. Mathematical experts will say: Triangles are more stable.

Foodies say: You can eat the filling in one bite with triangular rice dumplings!

Saving on materials: The materials used to make zongzi vary from place to place, but they are basically the leaves of plants. The leaves are wide and long and tough, but they are leaves after all, and their width is limited.

The triangular wrapping method only requires 1 or 2 leaves, while the rectangular shape requires about 3 or 4 leaves.

Therefore, wrapping the rice dumplings in a tetrahedral shape can save raw materials without losing the fullness.

3. Reasonable shape: Triangular rice dumplings can use complete leaves on all four sides, without unnecessary bending. If the rice dumplings are made into a square shape, then any surface must be connected to other surfaces without causing the rice to leak out.

Fold the leaves and buckle them inward. The leaves are tough along the direction of the plant fibers, but they are easy to break in the vertical direction.

From a geometric point of view, let’s analyze the doorway in Zongzi: First of all, unlike the instability of parallelepipeds (for example, the cubic frame can swing left and right), the properties of tetrahedrons are very stable. As long as the lengths of the six edges are determined, you can spell out

A unique tetrahedron.

Therefore, tetrahedral rice dumplings are less likely to deform.

Although the four-cornered rice dumplings are not necessarily regular tetrahedrons, the four sides are usually the same isosceles triangles. If you take apart the surface of this tetrahedron, you can get two equal rhombuses, which means using two similar slender leaves.

Just enough to wrap it up and make the best use of it.

Another characteristic of the regular tetrahedron is that it has four triple axes of rotational symmetry and six symmetry planes. Each two opposite sides are perpendicular to each other. This shows that no matter how the rice dumplings are placed in the container, they will look the same.

It lies flat and neatly, and does not give people the feeling of lying on its side.

The right triangular pyramid also has a center of gravity, which is also the center of its circumscribed sphere and inscribed sphere. It is on the line connecting the vertex and the center of gravity of the base. Divide this height into 3:1, which is one-quarter of the distance from the ground.

at.

Therefore, if you use toothpicks or chopsticks to tie up the rice dumplings and find this point, you can best ensure that the force is even and will not fall or break easily.

A small tetrahedral rice dumpling contains so much geometric knowledge.