I appreciate that, but it requires creating an account, and for people who have a gazillion other things to be doing, taking the time to create Yet Another Account on Yet Another System just for the one article is something most people will pass on.

It may not have a financial cost, but it certainly has an opportunity cost, and contributes to "Account Fatigue".

But loved the proof of Heron's formula, and I'm pleased to be able to say thank you in person, and make sure I give credit when I use it for the Math Club talks I do.

Great work ... feel free to contact me if you are so inclined, or put an email address in your profile.