Embedded Files
Lesson overview
Lesson overview
In this lesson you will:
learn about the inverse of sin, cos and tan
practise finding unknown angles.
Activity 1 - What is the inverse of sin, cos and tan?
Activity 1 - What is the inverse of sin, cos and tan?
During this lesson you will need to find the missing angle within each right-angled triangle.
As we know each angle is associated with a trigonometric function (sin, cos and tan) within an equation (SOH, CAH or TOA).
But when solving equations involving trigonometric functions, we need to use inverse functions. So what are they?
Task
Task
Complete the interactive to learn about the inverse functions of sin, cos and tan.
Activity 2 - How to find an unknown angle
Activity 2 - How to find an unknown angle
Task 1
Task 1
Watch these videos to learn how to find unknown angles.
Finding Angles with Trigonometry (1 of 2: What's an Inverse?)
Duration: 4:49
Finding Angles with Trigonometry (2 of 2: Using the Calculator)
Duration: 7:54
Task 2
Task 2
Watch the video, SOHCAHTOA - Finding Missing Angles, and complete the practise questions to check you have understood the process.
SOHCAHTOA - Finding Missing Angles | Trigonometry | Maths | FuseSchool
Duration: 4:50
Task 3 - Applying your new skill
Task 3 - Applying your new skill
This embedded Geogebra app creates new triangles with an unknown angle for you to practise your skills.
Spend at least 10 minutes finding unknown angles.
Use your exercise book or folder to show all the working, including a rough sketch of the triangle with sides and angles labelled.
Use the check box in the app to check your answer before you press the new button for the next triangle.
If you are struggling go back and re-watch the videos in task 1 and 2.
Activity 3 - Play mini golf with trigonometry
Activity 3 - Play mini golf with trigonometry
Click on the image to open the Exploring trig ratios page on the Math Interactives website.
Note: The page takes a little while to load so give it a minute.
Click on the tiny "bigger" button in the top right hand corner to make the interactive larger and easier to use.
Play the golf game by correctly identifying the sides of the triangles, which equation to use and substituting in the values.
Activity 4 - Solving mixed problems
Activity 4 - Solving mixed problems
Return to the Trigonometry interactive on the Transum.org website. This time we will start with Level 7.
Click on the image to open the Trigonometry interactive in a new tab.
Activities too hard?
Activities too hard?
Practise estimating angles with this Alien angles game on the Math playground website.
Activities too easy?
Activities too easy?
Watch the video, Finding Unknown Angle with Trigonometry: Example 1 on YouTube to learn how to work with angles measured in degrees and minutes.
Use the Bearings interactive on Geogebra to compare compass bearings with true bearings. Move the red points around to change the angles.
Handing in your work
Handing in your work
Don't forget to hand in the work you completed today!
Your teacher will have told you to do one of the following:
Upload any digital documents you created and any photos you took of your written work to your Learning Management system (MS Teams, Google Classroom for example).
Email any digital documents you created and any photos you took of your written work to your teacher.
Make sure you keep any hand written work you did in your exercise book or folder as your teacher may need to see these when you are back in class.
Student reflection
Student reflection
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