Quick Quiz Find the unknown angle, show working TOA = = 30.379… = 30 22 44.85

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

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 )

Rounding angles… On your calculator, we use the button to convert a decimal answer into degrees, minutes and seconds. For example: 45.2514 Becomes 45 15 5.04 degrees minutes seconds Remember that there are 60 seconds in a minute We can round our result to the nearest minute 45 15 (to nearest minute) 45 (to nearest degree) 5 round up leave same 15 30

Another example… Example 2: 30.75978 Becomes 30 45 35.21 degrees minutes seconds 30 46 (to nearest minute) 31 (to nearest degree) round up leave same 45 35 30

Your turn… Convert 70.6231 to degrees, minutes, seconds and round to the nearest minute 70 37 23.16 = 70 37 Convert 26.565 to degrees, minutes, seconds and round to the nearest minute 26 33 54 = 26 34 Find and round to the nearest degree 62 57 51.51 = 63

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

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

Examples….. TOA

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

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