[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.
[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.
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. 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). Because triangles are both identical, neither angle is the same. If two sides are equal, then the angles of the triangles are identical. The second angle of the triangle is equal to its farthest opposite angle. Therefore two triangles must be congruent just as anyone else is.