postulado 9, poligonos concavos ordenados 23
If we draw the diagonal in each one of them parallelograms consistent of a parallelogram divided in parallelogram of order ( m, r ) or ( r, m ) m more that r, r greater or equal that two pair, and delete them surplus, was obtained a polygon concave ordered of data ( m, r, r ) or ( r, m, r ) m greater than r, r greater than or equal than two pair.