Trigonometry

Measurement in History

The study of trigonometry began in 140 BC when Ancient Greek mathematicians invstigated the chords in a circle. The name trigonometry was first published in 1595 by Piticus and comes from the word trigons, which is Latin for triangle.

This chapter covers the following skills:

• calculating unknown sides of a right-angle triangle using the trigonometric ratios  SOH CAH TOA.
• finding unknown angles.
• solving practical problems.

The below game calculates the side lengths and/or angles of a triangle of any dimension. Click on 'full solution' to see how these angles are derived. Don't worry if you don't understand it all - everything will become clear soon!