Classify Angles and Angle Pairs

Front

What is an angle?

Back

An angle is formed by two rays that share a common endpoint, called the vertex.

Front

What are the types of angles based on their measures?

Back

1. Acute angle: less than 90° 2. Right angle: exactly 90° 3. Obtuse angle: more than 90° but less than 180° 4. Straight angle: exactly 180°

Front

What is a supplementary angle?

Back

Two angles are supplementary if the sum of their measures is 180°.

Front

What is a complementary angle?

Back

Two angles are complementary if the sum of their measures is 90°.

Front

If one angle measures 30°, what is its supplementary angle?

Back

150° (because 30° + 150° = 180°).

Front

If one angle measures 45°, what is its complementary angle?

Back

45° (because 45° + 45° = 90°).

Front

What is a reflex angle?

Back

A reflex angle is an angle that measures more than 180° but less than 360°.

Front

How do you find the measure of an unknown angle in a pair?

Back

Use the equations: - For supplementary angles: x + y = 180° - For complementary angles: x + y = 90°.

Front

What is the measure of an angle if it is acute?

Back

An acute angle measures less than 90°.

Front

What is the measure of an angle if it is obtuse?

Back

An obtuse angle measures more than 90° but less than 180°.