A square of 16 cm square was cut into three pieces: R a right triangle with sides of 20 cm, 16 cm and 12 cm; B a right triangle with sides of 16 cm, 12.8 cm and 9.6 cm; V a quadrilateral with two right angles. How many different convex polygons (ie, the corners of which are all smaller than 180 degrees) can be form? Calculate their perimeter.