Angle Relationships

Front

What are vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always equal in measure.

Front

What are complementary angles?

Back

Complementary angles are two angles whose measures add up to 90 degrees.

Front

What are supplementary angles?

Back

Supplementary angles are two angles whose measures add up to 180 degrees.

Front

What are adjacent angles?

Back

Adjacent angles are two angles that share a common side and a common vertex but do not overlap.

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90 degrees.

Front

What is an obtuse angle?

Back

An obtuse angle is an angle that measures more than 90 degrees but less than 180 degrees.

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 degrees.

Front

What is a straight angle?

Back

A straight angle is an angle that measures exactly 180 degrees.

Front

If m∠1 = 45°, what is m∠2 if ∠1 and ∠2 are complementary?

Back

m∠2 = 45° (because 45° + 45° = 90°).

Front

If m∠3 = 120°, what is m∠4 if ∠3 and ∠4 are supplementary?

Back

m∠4 = 60° (because 120° + 60° = 180°).