Trigonometry

Welcome!

Welcome to the Trigonometry page! Just like with Pythagoras this page has also been designed so you can work through it in the order presented, but as always you can also jump to any section you want whenever you want!

Trigonometry is the study of angles and lengths in triangles and allows us to calculate a side length of a right-angled triangle without measuring it. All we need to know is one of the side lengths and an angle.

Labeling right-angled triangles

There are three sides to a right-angled triangle: we give them all special names. From the last section we found that the longest side is called the hypotenuse. The hypotenuse is always opposite the right angle.

The other two sides are called the opposite and adjacent sides. Watch the video to see how these are labeled.

SOH CAH TOA

There are three buttons on your calculator you probably haven't used before: sin, cos, and tan. This video explains what each of these buttons do, which ones to use - and most importantly - what SOH CAH TOA means!

Your turn - SOH CAH TOA

Have a go at this worksheet on labeling the sides of a triangle and figuring out whether to use sin, cos or tan. Complete the exercises in your book and check your work with the answers on the last page.

Finding-Side-Lengths.pdf

In this section we are going to use pull everything together to calculate side lengths of a right-angled triangle, without measuring them. The video below shows you how it is done. Feel free to skip ahead to the section you are interested in:

Recap [0:00 - 2:04]
Calculating side lengths of a triangle using SOH CAH TOA [2:05 - 10:32]
Practice [10:33 - 12:40]: Once the question has popped up, pause the video and try it yourself before checking the answers

Your turn - calculating side lengths

Complete this worksheet in your book and check your work with the answers on the last page. Remember that if you get stuck you can watch the video again or ask your teacher for help.

(For more practice, check out Beta Textbook page 277-279 and 281-282)

Trigonometry To Find Lengths.pdf

Calculating angles

Hopefully at this point you are pretty confident with calculating side lengths of right-angled triangles.

If so, watch this video which explains how to calculate missing angles if you know two side lengths.

If you're not confident to move on yet, work through the exercises and videos again or check with your teacher.

Your turn - calculating angles

Complete this worksheet in your book and check your work with the answers on the last page.

(For more practice, check out Beta Textbook page 297-301)

Unknown angles.pdf

Mix it up!

This worksheet has a mixture of everything you have learned so far in this section. Have a go once you are confident with everything so far.

When you are ready, move on to the MyMaths quizzes below:

Mix it up.pdf

Quiz yourself!

Now that you've had lots of practice, you can quiz yourself on MyMaths. Once you've logged in you can search for the task in the Library. Follow the pathways:

Library > Measurement and Space Geometry > Trigonometry > Trig Missing Sides

Library > Measurement and Space Geometry > Trigonometry > Trig Missing Angles

Library > Measurement and Space Geometry > Trigonometry > Angle of Elevation

The screenshot below also shows you how to find this.

I've done all that, now what?

If you've gone through the video, tried the worksheets and MyMaths quizzes then there's a couple things you can do:

Need more practice?

- Rewatch the video
- Go back over the previous worksheets
- Redo the MyMaths activities
- Check out the practice questions in the Beta textbook
- Ask your teacher for some help

Ready to move on?

Ask your teacher about doing the practice test

Feeling confident?

Extend yourself with the 3D Trigonometry problems below

3D Trigonometry

Watch the video below about finding angles in 3D situations using Trigonometry and after that you can try the worksheet. There are answers at the end so you can check to see if you're on the right track!

(For more practice, check out Gamma Textbook page 307-310)

3D Trigonometry Worksheet.pdf

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