1. Applications of Trig Functions
EQ: How do I use trigonometry in real-life application problems?

2. Angles of Elevation and Depression

3. 4. A closed circuit television camera is mounted on a wall 7
4. A closed circuit television camera is mounted on a wall 7.4 feet above a security desk in an office building. It is used to view an entrance door 9.3 feet from the desk. Find the angle of depression from the camera lens to the entrance door. ?
7.4 feet ?
9.3 feet

4. 5. The world’s longest escalator is the Leningrad Underground in Lenin Square. The escalator has an angle of elevation of 10.36° and a vertical rise of ft. Find the length of the escalator. ?
195.8 feet
10.36°

5. 6. Find the height of a flagpole which casts a shadow of 9
6. Find the height of a flagpole which casts a shadow of 9.32 m when the sun makes and angle of 63 to the horizontal.
63 ?
63
9.32 m

6. 7. A train must climb at a constant gradient of 5
7. A train must climb at a constant gradient of 5.5 m for every 200 m of track. Find the angle of incline.
200 m
5.5 m ?

7. EQ: How do you find the area of a triangle using trigonometry?
Areas of Triangles
EQ: How do you find the area of a triangle using trigonometry?

8. Review
A=1/2(bh)

9. What happens if you don’t know the height???
There are some cases where you don’t need the height to find the area…

10. What happens if you don’t know the height???
There are some cases where you don’t need the height to find the area…
You have two sides and the included angle

11. Labeling a Triangle
If you have a triangle ABC with angles A, B, C the sides opposite these angles are a, b, c

12. Formula for the Area of a Triangle when you have 2 sides and the included angle.
The area of triangle is half of the product of two sides and the sine of the included angle

13. Find the area of the triangle: