1. Warm Up 1/15 Solve for x, the missing side, in the triangles below. 1.2.

2. Announcements Test on Friday Online homework 10-3 due Sunday Night

3. Inverse Trig Functions If we know the ________ lengths of a triangle, but not the ________measures we can use ___________ trig functions to solve for θ. SIDE INVERSE ANGLE

4. Inverse Trig Functions sin -1 cos -1 tan -1 **Used to find angle measures **Located in the Trig button section

5. How it Works If sin(θ) = 5/9, then θ = sin -1 (5/9) Plugging into our calculator we get sin -1 (5/9) = _______

6. Now You Try! (Round to the nearest degree) 1. sin(A) = 4/6 A = ____________ = ________ 2. cos(B) = 5/7 B = ____________ = ________ 3. tan(R) = 1 R = ____________ = _______ 4. sin(Z) = 8/9 Z = ____________ = ________ 5. cos(θ) = 3/12 θ = ____________ = ________ 6. tan(X) = 15/5 X = ____________ = ________

7. Important Side Note ***Sometimes you will see the inverse trig functions written as arcsin, arccos, and arctan….they do the exact same thing!

8. Finding a Missing Angle 1.Mark the __________ that you are looking for. 2.Label the given ________ in relation to the angle that you need to find.(opp, adj, hyp) 3.Decide which _____________________ (sin, cos, or tan) you can write with the sides that you have been given. 4.Write out the __________________. 5.Use __________________ (sin -1, cos -1, or tan -1 ) to tell you the missing angle measure. ANGLE SIDES TRIG FUNCTION EQUATION INVERSE TRIG

9. EXAMPLES

11. Homework Online HW 10-3

12. Classwork Pg. 439 #12-17, 20-22