1. θ

2. + Counter clockwise - clockwise Initial Ray Terminal Ray Definition of an angle

3. Radian Measure

4. r r 1 Radian  57.3 o 360 o = 2 π radians 180 o = π radians Definition of Radians C= 2 πr C= 2 π radii C= 2 π radians

5. Unit Circle – Radian Measure

7. Degrees

8. Converting Degrees ↔ Radians Recall Converts degrees to Radians Converts Radians to degrees more examples

9. Coterminal angles – angles with a common terminal ray Initial Ray Terminal Ray

10. Coterminal angles – angles with a common terminal ray Initial Ray Terminal Ray

11. Trigonometric Ratios

12. θ Reference Angle Adjacent Leg Hypotenuse Opposite Leg Basic ratio definitions

13. Circle Trigonometry Definitions (x, y) Radius = r Adjacent Leg = x Opposite Leg = y reciprocal functions

14. Unit - Circle Trigonometry Definitions (x, y) Radius = 1 Adjacent Leg = x Opposite Leg = y 1

15. Unit Circle – Trig Ratiossincostan (+, +) (-, -) (-, +) (+, -) Reference Angles Skip π/4’s

16. Unit Circle – Trig Ratiossincostan (+, +) (-, -) (-, +) (+, -)

17. Unit Circle – Trig Ratiossincostan (+, +) (-, -) (-, +) (+, -) sincostan 1 1 0 0 0 0 0 0 Ø Ø (0, -1) (0, 1) (1, 0)(-1, 0) 0 /2 π Quadrant Angles View π/4’s

18. Unit Circle – Radian Measuresincostan (+, +) (-, -) (-, +) (+, -) Degrees 1 sincostan 1 1 0 0 0 0 0 0 Ø Ø 0 /2 π Quadrant Angles

19. A unit circle is a circle with a radius of 1 unit. For every point P(x, y) on the unit circle, the value of r is 1. Therefore, for an angle θ in the standard position: