1 6 Measuring Angles Essential Questions 1 How

1. 6 Measuring Angles Essential Questions: 1) How do you measure angles? 2) What are the special angle pairs?

• An angle consists of two rays that have the same endpoint. • The rays are the sides of the angle. • The endpoint is the vertex of the angle. A C B

Practice • Name the angles in the figure P Q S R

• The measure of an angle is written in units called degrees (°). • The measure of ∠A is denoted by m∠A. B 3 2 1 A C 1. Place the center of the protractor over the vertex A. 2. Align the protractor with one side of the angle. 3. The second side of the angle crosses the protractor at the 60° mark. So, m∠BAC = 60°

Measuring Angles

• Angles have measures greater than 0° and less than or equal to 180°.

Ex 3 - Using the Angle Addition Postulate

• Two angles are adjacent angles if they share a common vertex and side, but have no common interior points. Common side 1 2 Common vertex <1 and <2 are adjacent angles

Practice • Tell whether the numbered angles are adjacent or nonadjacent. 1 3 2 4 5 6

Ex 4 - Identifying Angle Pairs

Ex 5 - Making Conclusions

Summary • Answer the essential questions in complete sentences. 1) How do you measure angles? 2) What are the special angle pairs? • Study Questions: Write 2 -4 study questions for the left column to help you study and explain your notes.