👉 In mathematics, concentric circles are geometric shapes that share a common center. These shapes have diameters that are equal in length to their radii and can be considered as "inner" or "outer" versions of each other. The concept is named after Archimedes, who used concentric circles to illustrate his famous principle that the sum of the interior angles on a straight line is 360 degrees. In geometry, concentric circles are fundamental in many areas, including calculus and differential
