This is wonderful - thank you!!!

Now this problem reminds me of a similar statement that my high school math teacher had mentioned 40 years ago. I am not a mathematician (only a hobby mathematician using math in medical research - but i like these pure math problems).

So can you help to analytically show the following - which has a similar structure:

a=16 and a=18 are the only two numbers for which a rectangle (or square) can have the same value a for its circumference and its area ?

Thank you. Sorry if it is trivial.