The angles that occupy the same relative position at each intersection where a straight line crosses two others. If the two lines are parallel, the corresponding angles are equal.

Back

Vertical Angles

Front

Angles that are opposite each other when two lines cross, they share the same vertex.

Back

Adjacent Angles

Front

Two angles next to one another sharing the same vertex and a common side.

Back

Complementary Angles

Front

Two angles are complementary when they add up to 90 degrees.

Back

Supplemental Angles

Front

Two angles are supplemental when they add up to 180 degrees.

Back

Alternate Interior angles

Front

When two lines are crossed by another line (called the transversal), the pairs of angles on opposite sides of the transversal. Inside and Opposite.