Problem description:
In other words, it is proved that this problem is similar to the conditions after ∵∴, such as ∴AB‖CD (the same angle is equal and two straight lines are parallel).
I gave an example of the condition in brackets, and there are many others. Please help me. Thank you.
Analysis:
I'll do it.
Two triangles with equal angles are similar.
Two figures in proportion on both sides are similar.
Two triangles with proportional sides and equal included angles are similar.
A triangle with two equal angles and a side length of 1
A triangle with two equal sides is congruent.
The distance from the intersection point of the bisector of a triangle to the three sides is equal.
The distance from the intersection of the perpendicular lines of three sides of a triangle to each vertex of the triangle is equal.
The obtuse angle formed by the intersection of bisectors of two corners of a triangle is 90 degrees+half of the third triangle.
The included angle of the line perpendicular to the waist of the isosceles triangle is half of the vertex angle.
Draw a straight line through the diagonal intersection of the parallelogram, and divide the parallelogram into two congruent figures.
The diagonal sum of the quadrilateral formed by any four points on a circle is equal to 180 degrees.
The center line of the hypotenuse of a right triangle is equal to half of the hypotenuse.
If a right triangle has an angle of 30 degrees, its opposite side is equal to half of the hypotenuse.