1. Geometry Notes Lesson 5.3B Trigonometry
T.2.G.6 Use trigonometric ratios (sine, cosine, tangent) to determine lengths of sides and measures of angles in right triangles including angles of elevation and angles of depression
T.2.G.7 Use similarity of right triangles to express the sine, cosine, and tangent of an angle in a right triangle as a ratio of given lengths of sides

2. Solving for unknown values
Steps: 1. 2. 3. 4.
Label the sides as: opposite, adjacent, hypotenuse.
Decide which trig ratio is needed:
(sine, cosine, or tangent).
Set up Equation
Use Calculator to Solve.

3. Example #1 :
Find x. Round your answer to the nearest tenth. 57
50 x

4. Example #2
Find x. Round your answer to the nearest tenth.
51 18 x

5. Example #3
Find x. Round your answer to the nearest tenth. x
46 3

6. Example #4
Find x. Round your answer to the nearest tenth. x
31 18

7. Now You Try…
Find x. Round your answer to the nearest tenth. x
46 3

8. Now You Try…
Find x. Round your answer to the nearest tenth. x
31 18