计蒜之道-初赛2 A. 联想公司的 logo 设计

AcceptCode

#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<string>
#include<cmath>
#include<algorithm>
using namespace std;
#define pi 3.141592653589793238462643383249901429
int main()
{
double l1,l2,tht;
double r1,r2,r1_r2,wide;

cin>>l1>>l2>>tht;

r1=l1/2,r2=l2/2;
tht = (tht*pi)/180;
r1_r2 = sqrt( r1*r1 + r2*r2 - 2*r1*r2*cos(tht) );
wide = r1 + r2 + r1_r2;

printf("%.10lf\n",pi*(wide/2)*(wide/2));
}