Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to prove similar triangles [title] Define the angle-angle (aa) theorem. [step] Two triangles can be proved similar by the angle-angle theorem which states: if two triangles have two congruent angles, then those triangles are similar. [substeps] This theorem is also called the angle-angle-angle (aaa) theorem because if two angles of the triangle are congruent, the third angle must also be congruent.

Ending1: This is because the angles of a triangle must sum to 180 °. [title] Identify the measure of at least two angles in one of the triangles. Ending2: There are four angles of a triangle which are equally equal. In the example above, there are four angles of a triangle opposite one another (or two sides). Ending3: Because triangles are both identical, neither angle is the same. If two sides are equal, then the angles of the triangles are identical. Ending4: The second angle of the triangle is equal to its farthest opposite angle. Therefore two triangles must be congruent just as anyone else is.

Answer format: ending1/ending2/ending3/ending4