Ultimate Circle area circumference radius calculator

Input >>> Is This Number



Then a Circle has:


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The circle calculator could help you find the area, circumference or radius of a circle. If you know one of the variable of a circle you can calculate the other 3 unknowns.

Area of a circle: A = πr2 = πd2/4

Circumference of a circle: C = 2πr = πd

Where, r = radius, C = circumference, A = area, π = pi = 3.14159

Chord, secant, tangent, radius, and diameter

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