I’m having a hard time creating a Pythagorean Theorem Calculator using the HTML formaction attribute. Please, any help would be really appreciated.
Do you mean that you don’t know where to start?
Identify what’s stopping you, whatever it may be. That gives you something to start working on.
Since you know you’ll be making a html form, maybe start with that? And then figure out how to serve the form, and how to reply to it. See how the overall problem breaks apart into smaller ones? Keep breaking things apart until you have solvable small problems, solve them one at a time and move on to the next.