Unit circle

The unit circle is like a special circle that helps us learn important math. It has a radius (the distance from the center to the edge of the circle) that is exactly 1. This means all points on the unit circle are exactly 1 unit away from the center. The unit circle is useful because it always shows us the same angles. Some angles are especially useful for math, like pi (3.1415...), and the unit circle helps us remember exactly what those angles are and also helps us calculate other angles with them.