1. Section 12-1a Trigonometric Functions in Right Triangles

2. Then
Now
Objectives
You used the Pythagorean Theorem to find side lengths of right triangles.
Find values of trigonometric functions for acute angles.

3. Common Core State Standards
Mathematical Practices
6) Attend to precision.
Common Core State Standards

4. Trigonometry is the study of relationships among the angles and sides of a right triangle. A trigonometric ratio compares the side lengths of a right triangle. A trigonometric function has a rule given by a trigonometric ratio.
Vocabulary

6. Find the values of the six trigonometric functions for angle θ.
Example 1

7. Find the values of the six trigonometric functions for angle θ in each triangle.
Example 1

8. In a right triangle, ∠A and ∠B are acute
In a right triangle, ∠A and ∠B are acute. If tan A = , what is cos A?
Example 2

9. In a right triangle, ∠A and ∠B are acute
In a right triangle, ∠A and ∠B are acute. If cos A = 1 2 , what is tan A? In a right triangle, ∠A and ∠B are acute. If sin B = 3 8 , what is tan B?
Example 2

11. Use a trigonometric function to find the value of x
Use a trigonometric function to find the value of x. Round to the nearest tenth if necessary.
Example 3

12. Use a trigonometric function to find each value of x
Use a trigonometric function to find each value of x. Round to the nearest tenth if necessary.
Example 3

13. p.795 #3, 13, 15, 17, 21 – 27
Homework