Three-line integration means that the bisector of the top angle, the height on the bottom edge and the center line on the bottom edge of an isosceles triangle coincide with each other (referred to as "three-line integration of isosceles triangle" for short)

This is the isosceles triangle theorem, which can be used directly.

This theorem can also be reversed. A triangle is an isosceles triangle if the bisector of the top angle, the height on the bottom edge and the midline on the bottom edge coincide.

Hope to adopt

What does "three lines in one" mean in mathematics?

Generally speaking, in an isosceles triangle (an equilateral triangle is also acceptable), the midline, the high line and the angular bisector are connected into a whole.

What is three in one?

The height line, median line and median vertical line on the same base of an equilateral triangle are on the same straight line.

What is the geometric language of three lines in one?

The bisector of the top angle, the median line on the bottom edge and the height on the bottom edge of the isosceles triangle coincide with each other.