I am having a hard time on how to prove traingles are similar

⚑ Flag

If the lengths of the sides of two or more triangles are porportional, the triangles are similar. Even easier to remember, similar triangles look the same, and the measures of the angles of one triangle match the corresponding angles of the other triangle.

An even better way: AA Similarity Postulate - If two angles from one triangle are congruent to two angles from another triangle, the triangles are congruent.