Angle Relationships

Front

Acute Angle

Back

angle that measures less than 90 degrees

Front

Obtuse Angle

Back

angle that measures more than 90 degrees

Front

Right Angle

Back

angle that measures exactly 90 degrees

Front

Straight Angle

Back

angle that measures exactly 180 degrees (a straight line)

Front

Linear Pair

Back

angles that are both adjacent (next to) and supplementary

Front

Vertical Angles

Back

pairs of opposite angles formed by two intersecting lines

Front

Corresponding Angles

Back

angles in the same relative position; "matching corners"

Front

Alternate Interior Angles

Back

angles inside a set of parallel lines and on opposite sides of the transversal

Front

Alternate Exterior Angles

Back

angles outside a set of parallel lines and on opposite sides of the transversal

Front

Adjacent Angles

Back

two non-overlapping angles with a common side and vertex