I became interested in exploring circles while helping out my niece with some problems involving arcs. So, I am just collecting here some interesting resources found online.

1) Why is a Circle 360 Degrees – Many of us have wrong notion that a circle is just 360 degrees . “A circle has 360 degrees, but it also has 400 gradients and approximately 6.2831853 radians. **It all depends on what *units* you measure your angles with**.”

2) How Egyptian’s measured circle’s area

3) In this blog, the author says Circles Are the Mother of All Inventions. Really? The author says ” A circle is not a “thing-in-itself.” It is a semantic fabrication that exists only in our imagination”