Geometry

Trigonometry Ratios & SOHCAHTOA
Calculating Angles with Sine, Cosine and Tangent
Exact Trigonometric Values
Pythagoras' Theorem
The Sine Rule: Finding Sides
The Cosine Rule: Finding Sides
Area of a Triangle

YOU ARE LEARNING:

Exact Trigonometric Values

Some values of Sin, Cosine and Tangent return exact values, and it is handy to remember these.

There are some values of Sin, Cos and Tan which return exact values, either as whole numbers, fractions or surds. This lesson will teach you the ones that are important to remember.

The important angles to be aware of are $30\degree$ , $45\degree$ and $60\degree$ We can use a simple diagram to show the exact values of trigonometry ratios at these angles.

What is $cos(45)$ ?

In general, memorising these values is a great addition to your maths toolbox.