# Unit circle facts for kids

In mathematics, a unit circle is a circle with a radius of 1. The equation of the unit circle is . The unit circle is centered at the Origin, or coordinates (0,0). It is often used in Trigonometry.

## Trigonometric functions in the unit circle

In a unit circle, where is the angle desired, and can be defined as and . Using the function of the unit circle, , another equation for the unit circle is found, . When working with trigonometric functions, it is mainly useful to use angles with measures between 0 and radians, or 0 through 90 degrees. It is possible to have higher angles than that, however. Using the unit circle, two identities can be found: and for any integer .

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Unit circle Facts for Kids. *Kiddle Encyclopedia.*