## 6.3 Sine and cosine

We learned how to use the tan relationship. Tan uses the opposite side and the adjacent side

You can also use the adjacent and the hypotenuse or the opposite side and the hypotenuse to calculate angles. These relationships are called sine (sin) and cosine (cos)

You get the sine of an angle by dividing the opposite side by the hypotenuse

sin (x) = opposite:hypotenuse

You get the cosine of an angle by dividing the adjacent side by the hypotenuse

cos (x) = adjacent:hypotenuse

It's very important to know when you have to use the sine, cosine or tangent... It depends on the information given in the exercise. There are multiple ways to get to know these. Here is a very annoying video where this man put it all in a song for us. I genuinely hope that it helps you and otherwise you have to figure out your own method to remember.

SOHCAHTOA https://www.youtube.com/watch?v=PIWJo5uK3Fo

Here you can practise using trigometric ratios correctly. The answers are on page 2. Please correct your own work and do not cheat. That is your own responsibility though!

Ratios Sin/cos/tan