View Compilation Error

0_0_26508183_1586.cpp: In function 'double area(Point, double, Point, double)':
0_0_26508183_1586.cpp:22:29: error: invalid type argument of unary '*' (have 'double')
       if(r1 < r2) return PI*r1*r1;
                             ^
0_0_26508183_1586.cpp:23:17: error: invalid type argument of unary '*' (have 'double')
       return PI*r2*r2;
                 ^