How do you find the ratio of any given polygon, and then using the "solve for x" method, and this would be done through having the information

 How do you find the ratio of any given polygon, and then using the "solve for x" method, and this would be done through having the information through the sides, such as (side ab, side bc, side cd, and da) and having that still be able to correlate to other polygons using the same methods, formula and ratio to solve for "x"