GCSE Maths – Introduction to Trigonometry

(SOHCAHTOA)

Trigonometry is the maths that involves sine, cosine and tangent. We usually shorten these to sin, cos and tan.
Sin, cos and tan are used to work out sides and angles in right angled triangles. They each represent a ratio involving two of the three sides of the triangle.

sin(x) = opposite ÷ hypotenuse

cos(x) = adjacent ÷ hypotenuse

tan(x) = opposite ÷ adjacent

This is where the phrase SOHCAHTOA comes in handy!

In this video lesson we look at how to label up our triangle and use sin, cos and tan to work out missing sides and missing angles. We also cover a more involved trigonometry exam question so you can see where the marks are awarded and some possible methods for answering these questions.