Meaning of similarity- theorems

In a pair of similar Polygons, corresponding angles are congruent.

Always

All acute triangles are similar

False

All isosceles triangles are similar.

False

Theorem 5-3

If three sides of one triangle are proportional to three sides of another triangle, then the triangles are similar. (SSS for similar triangles)

Theorem 5-2

If two sides of one triangles are proportional to two sides of another triangle and included angles are equal, then the triangles are similar. (SAS for similar triangles)

All equilateral triangles are similar

True

All isosceles right triangles are similar

True

All right triangles are similar

False