Drawing the center of gravity of any triangle ABC with ruler

Drawing the center of gravity of any triangle ABC with ruler

The center of gravity of a triangle is the point of intersection of the center lines of its three sides

As shown in the figure, if ∠ ABC is known, make an angle to make it equal to half ∠ ABC

This problem includes two basic drawing: (1) making bisector of an angle; (2) making an angle equal to a known angle
First, make the bisector BD of ∠ ABC; (detailed steps do not need to be described, because it is a basic drawing, we think you have mastered it)
Second: make ∠ def = ∠ abd (or ∠ CBD); (detailed steps do not need to be described, because it is also a basic drawing, we all think you have mastered. But the lines made in these two steps should be retained, which is called "retaining the traces of drawing")
Third: ∠ DEF is the angle sought
——————The picture is too simple, so you don't have to go up, do you?

In the triangle ABC, D is the midpoint of the AB side, AC = 4, BC = 6. Find the value range of the length of CD and make the central symmetry graph of CDB about D
We need to be quick

Double center line to e
CDB is equal to ade
AE=BC=6
SO 2

Is an equilateral triangle included in an isosceles triangle
If so, does an isosceles triangle have three or seven bisectors, heights, and midlines?

Equilateral triangle is a kind of isosceles triangle (special isosceles triangle), which has three bisectors, high and middle lines
The general isosceles triangle has 7 bisectors, high and middle lines