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

If two angles are vertical angles and one measures 45°, what is the measure of the other angle?

Back

45°

Front

What are complementary angles?

Back

Complementary angles are two angles that add up to 90°.

Front

What are supplementary angles?

Back

Supplementary angles are two angles that add up to 180°.

Front

What type of angle is 90°?

Back

A right angle.

Front

What type of angle is greater than 90° but less than 180°?

Back

An obtuse angle.

Front

What type of angle is less than 90°?

Back

An acute angle.

Front

What is a straight angle?

Back

A straight angle measures exactly 180°.

Front

If angle A is 30°, what is the measure of its complementary angle?

Back

60° (because 30° + 60° = 90°).

Front

If angle B is 120°, what is the measure of its supplementary angle?

Back

60° (because 120° + 60° = 180°).