UVa 10209 Is This Integration ?

题目链接：http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=41&page=show_problem&problem=1150

题意：求三块的面积

#include <cstdio>
#include <cmath>

const double PI = acos( -1.0 );

int main()
{
    double a;
    while( scanf( "%lf", &a ) != EOF )
    {
        double z = ( 1 - sqrt( 3.0 ) / 4.0 - PI / 6.0 ) * a * a;
        double y = ( 1 - PI / 4.0 ) * a * a - 2 * z;
        double x = a * a - 4.0 * ( y + z );
        printf( "%.3f %.3f %.3f\n", x, 4.0 * y, 4.0 * z );
    }
    return 0;
}