Warm-Up Find the following. 1.) sin 30 ◦ 2.) cos 270 ◦ 3.) cos 135 ◦

13.3 Radian Measure Central Angle – An angle with a vertex at the center of a circle. Intercepted Arc – Portion of the circle with endpoints on the sides of the central angle and remaining points within the interior of the angle.

Radian – Another way to measure angles. a radian is a central angle that intercepts an arc that is the same length as the radius of the circle How many radians are there in a circle? How can we find this?

Converting Between Radians and Degrees To convert degrees to radians, multiply by To convert radians to degrees, multiply by

Examples: Convert degrees measure to radians. 1.) 45 ◦ 2.) 225 ◦ 3.) 150 ◦

Convert from radians to degrees. 4.) Radians 5.) Radians6.) 2 Radians

Ex 7: Find the exact values of cos and sin of radians.