1. Do Now Find the value of each expression. Sin 60 ° Cos 30 ° Tan 270 °

2. Chapter 3 Radian Measure & Circular Functions
Section 3.1 – Radian Measure
Objective: SWBAT know the definition of radians, convert between degress and radians.
SWBAT find function values for angles.

3. A second way to measure angles is in radians.
Radian Measure
A second way to measure angles is in radians.
Definition of Radian:
One radian is the measure of a central angle  that intercepts arc s equal in length to the radius r of the circle.
In general,

4. Radian Measure

5. Radian Measure

6. Conversions Between Degrees and Radians
To convert degrees to radians, multiply degrees by
To convert radians to degrees, multiply radians by

7. Example: Degrees to Radians
Convert each degree measure to radians.
a) 60

8. Example: Radians to Degrees
Convert each radian measure to degrees. a)

9. Equivalent Angles in Degrees and Radians
6.28 2
360
1.05
60
4.71
270
.79
45
3.14 
180
.52
30
1.57
90 0
Approximate
Exact
Radians
Degrees

10. Equivalent Angles in Degrees and Radians continued

11. Class work
Convert each degree measure to radians. Leave answers as multiples of pi. 60 90
150
300
450

12. Convert each radian measure to degrees
π/3
7π/4
11π/6
-π/6
7π/10

13. Homework
Page 97 # 6-14 even and even