You will be most familiar with degrees. There are 360 degrees in a full circle. You will be less familiar with the grad. This is a decimal system in which there are 400 grad in a full circle i.e. 100 grad in a right angle. In this lesson we will look at radian measure.
Radians take advantage of the relationship between and measures in circles.
We write this as . You will see that some formulae are easier to use with radians. But their importance goes well beyond this. Almost all of your work from now on will be in radians, so make sure you can memorise all of the key angles in radians as soon as possible.