Source: wikibot/theorems-about-circles
= Theorems about circles
{wiki=Category:Theorems_about_circles}
Circles are fundamental shapes in geometry, and several important theorems govern their properties and behaviors. Here are some key theorems about circles: 1. **Circumference Theorem**: The circumference \\( C \\) of a circle is given by the formula: \\\[ C = 2\\pi r \\\] where \\( r \\) is the radius of the circle.