1. Devon wants to build a rope bridge between his treehouse and Cheng’s treehouse. Suppose Devon’s treehouse is directly behind Cheng’s treehouse. At a distance of 20 meters to the left of Devon’s treehouse, an angle of 52° is measured between the two treehouses. Find the length of the rope.
Problem of the Day

2. Section 12-1b Trigonometric Functions in Right Triangles

3. Then
Now
Objectives
You found values of trigonometric functions for acute angles.
Use trigonometric functions to find side lengths and angle measures of right triangles.

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

6. Find the value of x. Round to the nearest tenth if necessary.
Example 5

7. Find the value of x. Round to the nearest tenth if necessary.
Example 5

8. The angle formed by the line of sight from the swimmer and a line parallel to the horizon is called the angle of elevation. The angle formed by the line of sight from the lifeguard and a line parallel to the horizon is called the angle of depression.
Vocabulary

9. A ramp for unloading a moving truck has an angle of elevation of 32 degrees. If the top of the ramp is 4 feet above the ground, estimate the length of the ramp.
Example 6

10. A 14-ft long ladder is placed against a house at an angle of elevation of 72 degrees. How high above the ground is the top of the ladder?
Example 6

11. John stands 150 meters from a water tower and sights the top at an angle of elevation of 36°. If John’s eyes are 2 meters above the ground, how tall is the tower? Round to the nearest meter.
Example 6

12. p.796 #29 – 39, 47, 48
Homework