323 Angles and Their Measure Objective Students will

3/23 Angles and Their Measure Objective: Students will be able to find coterminal and reference angles. Students will also be able to find the arc length and area of a sector. EQ: How do I measure angles and put them in standard position? What are radians and how do they relate to degrees and trigonometry in general? Copyright © 2013 Pearson Education, Inc. All rights reserved

Finding Coterminal Angles Two angles with the same initial and terminal sides but possibly different rotations are called coterminal angles. Smallest angle made from the terminal side to x-axis is called the reference angle. It is always positive and < 90˚. Assume the following angles are in standard position. Coterminal and/or reference angle: a. 400° angle b. – 135° angle

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Definition of a Radian • One radian is the measure of the central angle of a circle that intercepts an arc equal in length to the radius of the circle.