Illustration to show that the bisectors of two supplementary adjacent angles are perpendicular to each…

Illustration of angles with parallel sides. "GH is parallel to and lies in the same direction as DE,…

Illustration showing four angles that can be used to define different relationships, such as adjacent,…

Illustration showing four angles that can be used to define different relationships, such as adjacent,…

Illustration showing six angles that can be used to define different relationships, such as adjacent,…

Illustration of supplementary angles. Two angles whose sum is a straight angle.

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow…

Illustration of supplementary angles. Two angles whose sum is a straight angle. This can be used tow…

Illustration that can be used to show supplementary angles. The angles form a straight line.

Illustration showing angles 1 and 2 are supplementary and angles ACD and DCB are supplementary. Also,…

Illustration of two angles whose sides are parallel, each to each, to show they are either equal or…

Illustration showing that when two parallel lines are cut by a transversal, the two interior angles…

Illustration used to prove "Two angles whose sides are perpendicular each to each are either equal or…

Illustration used to prove the theorem, "Two angles whose sides are parallel, each to each, are either…

Illustration used to prove the theorem, "Two angles whose sides are perpendicular, each to each, are…