2. Chapter 5.4 – Angles of elevation and depression
Trigonometry
Chapter 5.4 – Angles of elevation and depression

3. Todays lesson
Understand the difference between angles of elevation and depression.

4. Angles of elevation and depression
Watch video: g

5. * If you where at location A, you would have to ‘elevate’/raise your eyes from the horizontal line to look at location B.

6. * If you where at location C, you would have to lower your eyes from the horizontal line to look at location D.

8. Work examples
Watch video: How to solve problems.

9. Work examples

10. Exer 5.4
Entry:
1,3,6,7,9,10
Expected:
1,2,4,5,6,7,8,9,12,13
Accelerated:
1,2,4,5,6,9,10,12,13,14

11. Trigonometry
Chapter 5.5 – Bearings

12. Todays lesson I am able to understand and read a true bearing
I am able to understand and read a compass bearing.

13. What do we know about compass’

14. True bearing
True bearings give the angle in degrees in a clockwise direction from north.
Eg. The true bearing of A from B is 036°T.
Note: always written with 3 digits.

15. Compass bearing
Compass bearings are directions given in terms of turning a number of degrees east or west from north or south. It is also known as a conventional bearing.
Work out if the position is in the north or south ‘half’.
If in the north ‘half’ start at north and work out how many degrees the location is towards either west or east.
Write out your compass bearing.
The compass bearing of A from B is N36°E.

16. Direction of southeast (SE)
As a compass bearing, its written as S45°E.
As a true bearing, its written as 135°T

17. The directions exactly in between the four compass points of N, E, S, W have what bearings?
Northeast (NE) =
Southeast (SE) =
Southwest (SW) =
Northwest (NW) =
Write both true and compass bearings!
045°T or N45°E
135°T or S45°E
225°T or S45°W
315°T or N45°W

18. Exer 5.5
Q1,2,3,5,8,10,11,13,15