postulado 59, poligonos concavos ordenados 25
The length of the diagonal of the congruent squares or congruent rectangles that divides a polygon data ordered concave ( m, mm, n ) m greater that n, n greater or equal that one, is equal to the length of the sides of them square congruent or of them diamonds congruent in that is divided a square and a rhombus of order ( m, m ) m greater than or equal to two respectively, and this is mentally supposed that they built the polygon concave ordered.