Proving two triangles are similar two different ways

The video tutorial discusses how to determine if two triangles are similar. It begins by identifying two triangles within a given figure and suggests separating them for clarity. The instructor explains how to label the sides and angles of the triangles. Two methods for proving similarity are discussed: using angle-angle similarity and side-angle-side similarity. The instructor demonstrates how to set up and solve proportions to show that the triangles are similar, emphasizing the importance of congruent angles and proportional side lengths.

Explain the significance of the right angles in the triangles discussed.

What does it mean for two sides of triangles to be congruent in the context of similarity?