By Ella, 10th
Every unit circle has radius of 1 and is centered at the origin. It is a basic concept in Geometry and Trigonometry. The unit circle is used to understand the values of sine, cosine, and tangent functions for any angle in a right triangle.
The concept of the unit circle can be traced back to ancient Greece! Over the centuries people from all over the world have added to the knowledge of the unit circle. It has become the basis of trigonometry and is used extensively in fields such as physics, landscape architecture, engineering, computer science, and others.
Ella
Real Math In A Minute 
I remember learning the unit circle my senior year of high school in trigonometry class. It was 2007…probably before you all were born 😦
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