View Compilation Error

0_0_12214426_23704.cpp: In function `double minPerimeter(const std::vector<Point2D, std::allocator<Point2D> >&)':
0_0_12214426_23704.cpp:47: error: `sqrt' undeclared (first use this function)
0_0_12214426_23704.cpp:47: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12214426_23704.cpp:59: error: `fabs' undeclared (first use this function)