The general formula for the dimensions is the width (same as the height) is 3*1.618*x the length is 4*1.618*x where x can be any real POSITIVE number, including integer numbers, rational numbers or irrational numbers. Giving "x" arbitrary values on your choice, you will get respective values for the length and the width. So, with the given instructions, you have a happy opportunity to practice and exercise without borders.