1. Quick Quiz Find the unknown angle, show working TOA = = 30.379…=

2. Trigonometry What have we learnt? About SOH CAH TOA
How to find the length of an unknown side
How to find an unknown angle
Where to now?
How to round our angle measure
To use our knowledge in solving real life problems

3. All about angles… Angles are measured in degrees
Degrees can be divided into smaller units
There are 60 minutes in 1 degree (minute symbol is )
And there are 60 seconds in 1 minute (second symbol is )

4. Rounding angles…
On your calculator, we use the button to convert a decimal answer into degrees, minutes and seconds.
For example:
Becomes
degrees minutes seconds
Remember that there are 60 seconds in a minute
We can round our result to the nearest minute
(to nearest minute)
45 (to nearest degree) 5
round up
leave same 15 30

5. Another example… Example 2: 30.75978 Becomes 30 45 35.21
degrees minutes seconds
(to nearest minute)
31 (to nearest degree)
round up
leave same 45 35 30

6. Your turn…
Convert to degrees, minutes, seconds and round to the nearest minute =
Convert to degrees, minutes, seconds and round to the nearest minute =
Find and round to the nearest degree
= 63

7. Angles of Elevation & Depression
Angle of elevation is the angle of looking up, measured from the horizontal.

8. Angle of depression is the angle of looking down, measured from the horizontal.

9. Examples…..
TOA

10. Example 2…..
There are many different ways to approach this question.

11. Practice…. Practical problems: ex 14D Q4,5,6 (pg 504)
Using angles of elevation & depression in application: Complete any 5 questions from ex14G (pages 518,519)
If you would like to see more worked examples see page 516 and page 518 of your textbook