Area of a circle
Basic formula for the area enclosed by a circle of radius r.
別名: 円面積, circle area, area of a circle, えんのめんせき
数式
S = π × r^2
変数
| S | Area of the circle (m²) |
|---|---|
| r | radius of the circle (m) |
| π | pi (approx. 3.14159) (—) |
計算例
半径 r = 3 m の円の面積を求めよ。
S = \pi r^{2}
S = \pi \times 3^{2}
S = 9\pi \;\mathrm{m}^{2}