Answer
Domain: $0\lt x\lt100$
Work Step by Step
$x$ must be greater than $0$, otherwise the square would not exist. But, $x$ must be less than $100~cm$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.