Methods to prove that three angles are equal chicken scratch:

1. Triangle Interior Angle Sum Theorem: In a triangle, the sum of the three interior angles is always equal to 180 degrees. If all three angles are equal, then each angle is 180 degrees divided by 3, or 60 degrees.

2, equilateral triangle: if all three sides are equal in length, then the three angles must be equal. This is because in an equilateral triangle, the distance from each vertex to the midpoint of the opposite side is equal, so their corresponding angles are equal.

3. Isosceles Triangle: In an isosceles triangle, the two base angles are equal. This is because the midline of the base side divides the top angle into two equal parts, so the two base angles are also equal.

4. Using parallel lines: If two parallel lines are cut by a third line, then the congruent (or interior) angles are equal. In a quadrilateral, if two sets of opposite sides are each parallel, then two sets of opposite angles are each equal.

5. By trigonometric functions: In right triangles, trigonometric functions can be used to prove that the angles are equal. For example, the sine function sin(A)=sin(B) can be used to prove that two angles A and B are equal.

6. Using four points *** Circle: If all four points are on the same circle, then the angles are complementary, i.e., the opposite angle of one angle is equal to the complementary angle of the other.

Triangle is a geometric figure, a closed figure made up of three line segments that are not on the same line joined head to tail. Triangles have important applications in math and physics.

Properties of triangles include the following:

1. The sum of the interior angles of a triangle is 180 degrees, i.e., the sum of the three interior angles is constantly equal to 180 degrees.

2. The sum of the sides of a triangle is greater than the third side, and the difference between the sides is less than the third side.

3, the triangle has stability, that is, when subjected to external forces, its shape and size is not easy to change.

4, triangles can be divided into three categories: acute triangles, right triangles and obtuse triangles.

5, triangles have three high lines, three center lines, three angle bisectors and three sides on the median line.

6. Triangles have special points such as the center of gravity, the vertical center, the external center, the internal center and the paracenter.

7. Triangles have the property of similarity, i.e., two similar triangles have equal ratios of corresponding sides and equal corresponding angles.

8. Triangles have the property of congruence, i.e., two congruent triangles have equal corresponding sides and equal corresponding angles.