Geometry Angles and Lines

Two angles that share a common side and vertex, but do not overlap.

Two angles whose measures add up to 90 degrees.

Two angles whose measures add up to 180 degrees.

Angles opposite each other when two lines cross. They are always equal.

Lines that intersect at a 90-degree angle.

Lines in a plane that never meet. They are always the same distance apart.

A pair of adjacent angles formed when two lines intersect. Their measures add up to 180 degrees.

Angles in matching corners when two lines are crossed by another line (the transversal).

Angles on opposite sides of the transversal but inside the two lines. They are equal if the lines are parallel.

Angles on opposite sides of the transversal but outside the two lines. They are equal if the lines are parallel.