After you have learnt how to label a triangle,
you have to choose one of the trig functions: Sine, Cosine or Tangent.
These are the sin, cos and tan buttons on your calculator.
This page will show you multiple choice questions so you can practise this skill.
(If you want help with labelling a triangle see the previous lesson)
Captain Obvious: a triangle has three sides.
What you have to remember is that each trig function only talks about two of those sides.
Which two sides? That is something you have to memorise,
and we use the made up phrase SOH CAH TOA to help remember.
In the previous lesson,
you learnt that we call the three sides of the triangle: Opposite, Adjacent and Hypotenuse.
Let's pick two of those sides: the Opposite and Hypotenuse.
Their initials are OH. Look through SOH CAH TOA.
One of those words ends in OH, and begins with S. So those two sides are linked by the Sine function.
See if you can work out the rest.
For some questions you may have to swap the order of the sides in order to use SOH CAH TOA.
The above exercise told you which two sides to consider.
In the below exercise, you can practise working out for yourself the name of those two sides.
Two sides are indicated in this triangle: one by showing its length, the other is the side you are asked to find.
Finally: do both at the same time.
Two sides are indicated in this triangle, just as above.
Find the trig function which connects them.