1, the regular triangular pyramid ground is a regular triangle, each side is a (set by you), and each angle is 60;

2. The straight line connecting any vertex and opposite side of the regular triangle is not only the height of the regular triangle, but also the median line and bisector of the angle; The length of the center line is (root number 3) a/2;

3. The vertical line from the vertex intersects the ground (that is, the height of the regular triangular pyramid), the intersection point (that is, the vertical foot) is the midpoint of the regular triangle, and the center line of the regular triangle is divided into two sections: 1:2;

According to the above three items, you can already know the height and the length of the bottom edge, draw a diagram, and make clear the relationship between the straight line and the plane. According to Pythagorean theorem, it can be found that the oblique height and the side length-the oblique height, the height and the ground centerline 1/3 form a right triangle; The side, height and 2/3 line segments of the ground center line form a right triangle;

Judging from your appearance, you should forget it.

The calculation method of oblique height and side length of regular triangular prism has always been a quantitative relationship problem.

As for the distance from the midpoint of the bottom surface to the edge and vertex, after making the auxiliary line, use a similar triangle.