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Find a circle's area from its radius using A = πr². Below the tool you'll find a ready reference table for the common radii 1 through 10, so frequent values need no typing at all.
Area from radius with a reference table for radii 1–10.
A = πr²
| Symbol | Meaning |
|---|---|
| r | Circle radius (≥ 0) |
r = 5 → A = π × 25 ≈ 78.5398. Reference: r=1→3.1416, 2→12.5664, 3→28.2743, 4→50.2655, 5→78.5398, 6→113.0973, 7→153.938, 8→201.0619, 9→254.469, 10→314.1593.
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Full double-precision π (≈ 3.141592653589793); displayed results round to six decimals.
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Content updated: September 2026