Function to find equation of plane .
void equation_plane ( float x1 , float y1 , float z1 , float x2 , float y2 , float z2 , float x3 , float y3 , float z3 ) { float a1 = x2 - x1 ; float b1 = y2 - y1 ; float c1 = z2 - z1 ; float a2 = x3 - x1 ; float b2 = y3 - y1 ; float c2 = z3 - z1 ; float a = b1 * c2 - b2 * c1 ; float b = a2 * c1 - a1 * c2 ; float c = a1 * b2 - b1 * a2 ; float d = ( - a * x1 - b * y1 - c * z1 ) ; std :: cout << std :: fixed ; std :: cout << std :: setprecision ( 2 ) ; cout << " equation ▁ of ▁ plane ▁ is ▁ " << a << " ▁ x ▁ + ▁ " << b << " ▁ y ▁ + ▁ " << c << " ▁ z ▁ + ▁ " << d << " ▁ = ▁ 0 . " ; }