Explains angles and parallel lines through examples and a video lesson.

Intermath Dictionary's site defines terms relating to angles, gives examples, and offers interactive exercises.

If two triangles are similar, it means that all corresponding angle pairs are congruent and all corresponding sides are proportional. However, in order to be sure that two triangles are similar, you do not necessarily need to have...

For this task, students use a piece of string or another tool to measure the radius of the circle and then mark off the corresponding arc length on the unit circle as many times as they need to for 0, 1, 2, 3, 4, 5, and 6 radians. They...

See how two triangles are congruent it means that all corresponding angle pairs and all corresponding sides are congruent.

The goal of this task is to understand how congruence of triangles, defined in terms of rigid motions, relates to the corresponding sides and angles of triangles. Aligns with G-CO.B.7.