Draw each a circular arc about the points E1 and E40, there arise the intersections A and B. Draw a vertical straight line from point B through point A. Draw a parallel line too the segment AB from the point E1 to the circular arc, there arises the intersection D. Draw a circle arc about the point C with the radius CD till to the extension of the side length, there arises the intersection F. Draw a circle arc about the point E40 with the radius E40F till to the vertical straight line, there arises the intersection G and the angle E40GE1 with 36°. Draw a circle arc about the point G with radius E40G till to the vertical straight line, there arises the intersection H and the angle E40HE1 with 18°. Draw a circle arc about the point H with radius E40H till to the vertical straight line, there arises the central point M of the circumcircle and the angle E40ME1 with 9°.