1. Concept

2. Example 1 Draw an Angle in Standard Position A. Draw an angle with a measure of 210° in standard position. 210° = 180° + 30° Draw the terminal side of the angle 30° counterclockwise past the negative x-axis. Answer:

3. Example 1 Draw an Angle in Standard Position B. Draw an angle with a measure of –45° in standard position. Answer: The angle is negative. Draw the terminal side 45° clockwise from the positive x-axis.

4. Example 3 Find Coterminal Angles A. Find an angle with a positive measure and an angle with a negative measure that are coterminal with 210°. positive angle: 210° + 360° = 570° negative angle: 210° – 360° = –150° Answer: 570° and –150°

5. Example 3 Find Coterminal Angles B. Find an angle with a positive measure and an angle with a negative measure that are coterminal with –120°. positive angle: 120° + 360° = 240° negative angle: 120° – 360° = –480° Answer: 240° and –480°

6. Concept

7. Example 4 Convert Between Degrees and Radians A. Rewrite 30° in radians. Answer:

8. Example 4 Convert Between Degrees and Radians Answer: –300° B. Rewrite in degrees.

9. Concept

11. Example 5 Find Arc Length TRUCKS The steering wheel on a monster truck has a radius of 11 inches. How far does a point on the steering wheel travel if the wheel makes four fifths of a rotation? Step 1Find the central angle in radians. 

12. Example 5 Find Arc Length ≈ 55.3 in.Use a calculator to simplify. Answer: A point on the steering wheel will travel about 55.3 inches after four fifths of a rotation. Step 2Use the radius and the central angle to find the arc length. s = r  Write the formula for arc length.