In a right-angled triangle, the sides and the angles are connected by three trigonometric ratios.
The three trig ratios are:
A quick way to remember this is to memorise the word
SOHCAHTOA
Example
Use the side lengths of this triangle to state the value of cosθº ?
Answer
Label the sides adjacent, opposite and hypotenuse in relation to the angle θº.
SOHCAHTOA
The side adjacent to the angle θ has length 3.
The hypotenuse has length 5.
The correct trig ratio is COS so cos θº= 3/5
