1, graphs with equal corresponding angles and unequal corresponding edges are all similar; Figures with equal corresponding angles and equal corresponding edges are congruent.

In the ninth grade, I mainly studied triangles. Of course, we should also know that all equilateral triangles are similar, all squares are similar, ... that is, all regular N-sided polygons are similar.

(1) isosceles triangle: isosceles triangles with equal vertex angles are similar; Similar isosceles triangle with equal base angle; The equilateral triangle is similar.

(2) Right triangle: In addition to right triangle, there is a similar angle corresponding to equal right triangle; The isosceles right triangle is similar.

(3) Arbitrary triangle: a triangle with two angles corresponding to equality is similar.

(4) The internal angles of similar triangles are equal.

(5) congruent triangles is a special kind of similar triangles. Their corresponding angles are all equal, and their corresponding sides are also equal.

2. A proportional triangle with two sides is similar triangles, such as a/a'=b/b'