Which three lines of a triangle have the same distance from three sides?

The point on the hypotenuse of a right triangle is as high as the intersection of two right angles, and the photography theorem can be derived. This can be used to deduce the midline of a triangle through the similarity of triangles: the midline of a triangle is parallel to the bottom and equal to half of the bottom. What's more, the teacher said that if a triangle has four points and two opposite midpoints, connect a diagonal line first, and then connect this midpoint with the known midpoint. If the midline theorem of a triangle is known, the midpoint of two adjacent sides of a quadrilateral is often connected with a diagonal, and then the midline of the triangle is used to prove the midline of the triangle: the distance between a point on the perpendicular line of a line segment and the two endpoints of the line segment is equal to one point; The median vertical lines of three sides of a triangle intersect at a point on the median vertical line of a line segment, and the distance between the point and the three vertices is equal; Angle bisector of triangle: the distance between the points on the angle bisector and the two sides of the angle is equal. A point equal to the inside of an angle and equidistant from both sides of the angle. On the bisector of this angle, the three bisectors of the triangle intersect at a point, and the distance from the point to the three sides is equal. Some properties of isosceles triangle: two waists are equal, two base angles are equal, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, equilateral, mass: the right angle opposite to 30 degrees is half of the hypotenuse. Inverse Theorem of Pythagorean Theorem When the vertex of a right angle has a 45-degree angle, one of the other two angles is rotated and the other angle is put together, and their sum is equal to some properties of an obtuse triangle with a 45-degree angle: when an angle of 120 135 150 degrees appears, one side of the obtuse angle uses some of its adjacent complementary angle congruent triangles. Corresponding edges are equal, corresponding angles are equal, corresponding median lines are equal, corresponding angles are equal, bisectors are equal, perimeters are equal, and areas are equal. Some properties of similar triangles: the corresponding sides are proportional, the corresponding median line is proportional, and the median line of a high-proportion trapezoid is parallel to the two bases and equal to half of the sum of the two bases. I really can't remember this twice. I'll make it up when I remember.