Lesson 1: 4.1 Radian and Degree Measure
Duration of Days: 4
Lesson Objective
1. Describe angles.
2. Use radian measure.
3. Use degree measure and convert between degrees and radians.
4. Use angles to model and solve real-life problems.
How do you describe angles and angular movement?
trigonometry
angle
initial side
terminal side
standard position
coterminal
positive angles
negative angles
central angle
degrees
radians
TF.A.1: Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle
Use Khan Academy resources.
Students should be familiar with measuring angles in degrees. They will learn about measuring angles in radians in order to find the arc length of a circle, and linear and angular speeds. The study of radian measure will also prepare students to study trigonometric functions later in the chapter.
Radian measures of angles are involved in numerous aspects of our daily lives. For instance, you are asked to determine the measure of the angle generated as a skater performs an axel jumps.
Some students may use the wrong conversion when finding an angle in degrees or radians.
Some students may forget that the angle used in the arc length formula must be in radian measure.
Have students cover the figures with a piece of paper. After students have sketched the angles, have them remove the piece of paper and check their angles.
Use common assessments.
Pre-Calculus with Limits resources.