## What is trigonometry?

Trigonon means triangle in Greek

Metron means measure in Greek

Trigonometry is all about triangles. It helps us find the angles and lenghts of sides in triangles. Mankind has been working with trigonometry for thousands of years now. We have evidence that the Egyptians and Babylonians started calculating angles and lengths in triangles and we are still using it today in school. It's also used a lot in science and engineering, but also in sports and gaming.

In this chapter we're going to learn the basics of trigonometry. In year 2 you learned how to calculate the length of one side of a right-angled triangle using Pythagoras' theorem. You will recap this in the refresh exercises.

If you're interested in learning more about the history of trigonometry you can go to the EXTRA: In depth tab on this website.