Area of Circle Calculator
From Radius
From Diameter
From Area
Formula
A = πr² | C = 2πr | d = 2r
Frequently Asked Questions
What is the area of a circle?
Area = πr² where r is the radius. For a circle with radius 5: Area = π × 25 ≈ 78.54. You can also use diameter: Area = π(d/2)² = πd²/4.
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