1. Set calculators to Degree mode.
Lesson 8.3: Trigonometry
Set calculators to Degree mode.

2. Sides of a Triangle
Opposite:
Adjacent:
Hypotenuse: B C A

3. Practice
Name the opposite, adjacent, and hypotenuse sides for θ, θ’, and θ”.
θ: opp:
adj:
hyp:
θ’: opp:
adj: hyp:
θ“ opp: A B
θ" θ' C

4. Trigonometric Ratios B C A Sine: Cosine: Tangent: hypotenuse opposite
adjacent θ C A

5. Practice
sin A =
cos A =
tan A = B 4 θ C A

6. Practice A B C Find the sine, cosine, and tangent of each angle.
sin A = cos A = tan A =
sin B = cos B = tan B =
sin C = cos C = tan C = 12 A B 5 13 C

7. Inverse Trigonometric Ratios
Inverse Ratios:
Ex: sin A =
∠A =
cos B =
∠B = B θ C A

8. Practice
What is the value of each angle? B θ' 12 θ C A

9. Practice
What is the value of each angle? 15 A B 17 C

10. Solving for Sides B C A Solving for sides: Ex: What is the value of x?

11. Practice
What is the measure of each side? B x y
25o C A

12. 
Practice

13. Application
The peak of Mt. Everest is 8,848m high. If Euclid can see the peak at a 15o angle, then far is Euclid from Mt. Everest?

14. Challenge
Prove (sin A)2 + (sin B)2 = 1 B
c a b θ C A

15. Challenge

16. Classwork
Lesson 8.3, #1 – 7

17. Homework
p. 537, #1 – 17 all Quiz next class.
Complete Practice Exam.