AnnulusFree Annulus Calculator - Calculates the area of an annulus and the equation of the annulus using the radius of the large and small concentric circles.
CirclesFree Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.
Venn Diagram (2 circles)Free Venn Diagram (2 circles) Calculator - Given two circles A and B with an intersection piece of C, this will calculate all relevant probabilities of the Venn Diagram.