View Compilation Error

0_0_39236029_17338.cpp: In function 'int main()':
0_0_39236029_17338.cpp:29:30: error: 'sqrt' was not declared in this scope
   29 |            double x1 = (-b + sqrt(b * b - 4 * a * c)) / (2.0 * a);
      |                              ^~~~