Using the point H_c and the point M_a, construct a circle k(M_a,B) (rule W06);

% NDG: points H_c and M_a are not the same

Using the point H_c and the point M_b, construct a circle k(M_b,C) (rule W06);

% NDG: points H_c and M_b are not the same

Using the circle k(M_a,B), the circle k(M_b,C), the point H_c, the point M_a and the point M_b, construct a point C (rule W08);

% NDG: circles k(M_a,B) and k(M_b,C) intersect

% DET: circles k(M_a,B) and k(M_b,C) are not the same points H_c and C must be different

Using the point C and the point M_a, construct a point B (rule W01);

Using the point M_b and the point C, construct a point A (rule W01);