1. January 18 th in your BOOK, 4.2 copyright2009merrydavidson Happy Birthday to: Hira Saleem, Shayna Faith Richardson, Georgi Longee, Davin Henderson & Morgan Hatwig Get a calculator. Put the “mode” in degrees.

2. Special Right Triangles S O H C A H T O A

3. y x r Reciprocal functions Parent functions

4. Angles of elevation and depression (calculator) Line of Sight Angle of depression (you look DOWN) Line of Sight Angle of elevation (you look up)

5. Definitions An ANGLE OF ELEVATION is the angle between a horizontal line of sight from an observer to an object at a higher level. An ANGLE OF DEPRESSION is the angle between a horizontal line and the line of sight from an observer to an object at a lower level. (This is OUTSIDE of the special right triangle.)

6. 1) The angle of depression is measured from the top of a 43 ft tower to a reference point on the ground. Its value is found to be 63 o. How far is the base of the tower from the point on the ground? This line MUST be drawn in. 21.9 ft.

7. This line MUST be drawn in. 30.7 ft. 2) The angle of depression from a search light to its target is 58 o. How long is the beam of light, if the searchlight is 26 ft above ground?

8. 89.4 ft. 3) A NASA recovery helicopter hovers 75 ft above a space capsule. If the angle of depression to the recovery ship is 40 o, how far is the ship from the space capsule?

9. 4) Given 2 sides, find the included angle. A historic lighthouse is 200 yards from a bike path along the edge of a lake. A walkway to the lighthouse is 400 yards long. Find the acute angle between the bike path and the walkway. 200 yds walkway 400 yds What do you know? So what is the angle measure? 30 o Bike path

10. 5) Given 2 sides, find the included angle. A historic lighthouse is 200 yards from a bike path along the edge of a lake. A walkway to the lighthouse is 350 yards long. Find the acute angle between the bike path and the walkway. 200 yds 350 yds So what is the angle measure? Take sin -1 of each side. Bike path

11. 10 degrees 6) Find the angle of elevation from the bottom of the world’s longest slide, located in Peru, Vermont if the vertical drop of the ladder is 82 feet and the length of the slide is 460 feet. 460 82 ?

12. HW: WS 6-4