1. Converting Degree Measure to Radian Measure Convert to radian measure: a) 210 0 180 0  or  π rad ≈ 3.67 Exact radian Approximate radian b) - 315 0 To convert from degrees to radians, multiply by One half a rotation is Math 30-11

2. Converting Radian Measure to Degree Measure Convert to degree measure: a) = 120 0 b) = -15 0 c) 1.68 = 96.26 0 To convert from radians to degrees, multiply by Math 30-12

3. Benchmark Conversions Degrees Radians 30 0 45 0 60 0 720 0 Degrees Radians 0 90 0 180 0 270 0 360 0 McGraw Hill DVD Teacher Resources 4.1_178_IA 57.3 Math 30-13

4. Determining the Sector Angle or the Arc Length Determine the measure of the sector angle: 6.1 cm 5 cm Determine the arc length. 8 cm 70 0 Convert 70 0 to radians: a = 9.77 The arc length is 9.77 cm. θ is measured in radians Math 30-14

5. Determine the length of the arc of the peacock’s feathers. If the length of the arc of the parachute is 31.9 feet, how long is the outside cord? Convert 255 0 to rads θ is measured in radians Math 30-15

6. Problem Solving Determine the value of a. One rotation is 2 π radians Determine the length of the radius to the nearest whole number. Math 30-16

7. Conversion between Radians and Degrees Using Formula Page 175 2a,c,d, 3a,c,f, 4a,c,e,f 5b,c, 12a, 13a,c,d, 15, 16, 18 Math 30-17