Right angled triangles appear all over the place in physics:

  • If you know the length of two sides then you can find the length of the third

Pythagoras: Example A

This example shows how you can find the length of the third side of a triangle.

Pythagoras: Example B

This example shows how you can use pythagoras to solve a physics problem.

Trigonometry (Sin, Cos and Tan)

If you have a right angled triangle then you can do clever things:

  • If you know the length of one side and an angle you can calculate another side

  • If you know two sides you can calculate an angle

  • Once you know one angle, or two sides, you can calculate the other angle and other side

Trigonometry: Example A

A simple example using trigonometry to find a missing force.

Trigonometry: Example B

A worked example where an angle is calculated for a right angled triangle.

You may also be interested in...


Physics Online Shop

Enamel pin badges now available.


Only £5 including UK postage!

GCSE Physics Online Recommended for Home Learning

The following organisations have recently recommended these resources to support students who are learning from home during the Covid-19 crisis.


Follow me!

  • YouTube
  • Instagram
  • Twitter