Circumcircle Radius of a Triangle
Derived from the sine rule, a/sin A = 2R.
別名: circumradius, circumcircle, がいせつえん
数式
R = abc / (4S)
変数
| R | Radius of the circumcircle (m) |
|---|---|
| a | Side a (m) |
| b | Side b (m) |
| c | Side c (m) |
| S | Area of the triangle (m²) |
計算例
a = 3、b = 4、c = 5 の三角形（S = 6）の外接円半径を求めよ。
R = \dfrac{3 \times 4 \times 5}{4 \times 6}
R = \dfrac{60}{24} = 2.5