If you’re studying trig or calculus—or getting ready to—you’ll need to get familiar with the unit circle. **The unit circle is** **an essential tool used to solve for the sine, cosine, and tangent of an angle.** But how does it work? And what information do you need to know in order to use it?

In this article, we explain what the unit circle is and why you should know it. We also give you three tips to help you remember how to use the unit circle.