三角形面积外接圆内切圆

三角形面积

4 * area = sqrt((a + b + c) * (a + b - c) * (a + c - b) * (b + c - a))

OR

(海伦公式)

s = (a +b + c) / 2.0

area = sqrt(s * (s - a) * (s - b) * (s - c))

外接圆半径

R = (a * b * c) / sqrt(4 * b * b - (b * b + c * c - a * a) * (b * b + c * c))

内切圆半径

r = sqrt((a + b + c) * (a + b - c) * (a + c - b) * (b + c - a)) / (2 * (a + b + c))

#include <cstdio>#include <math.h>int main(){int a, b, c;scanf("%d%d%d", &a, &b, &c);float area, s;s = (a + b + c) / 2.0;area = sqrt(s * (s - a) * (s - b) * (s - c)); printf("%f\n", area);area = sqrt((a + b + c) * (a + b - c) * (a + c - b) * (b + c - a)) / 4.0;printf("%f\n", area);return 0;}