How to calculate the center of the circumcircle of the triangle formed by three geographic coordinates

Question

Where is the center of those 3 geographic coordinates as an example:

    double latA = 37.418436;
    double lonA = -121.963477;

    double latB = 37.417243;
    double lonB = -121.961889;

    double latC = 37.418692;
    double lonC = -121.960194;