Okay, the user wants me to translate "quarter-circle" into Hebrew. Let me start by breaking down the term. "Quarter" in Hebrew is רבע, and "circle" is חלון. But wait, "quarter-circle" is a specific term, so I should check if there's a standard translation for it.
I recall that in geometry, a quarter-circle is called רבע מעגל. Let me confirm that. Yes, "רבע" means quarter, and "מעגל" is circle. So combining them, it should be רבע מעגל. The user mentioned if the content is already in Hebrew, leave it as is. Since the input is in English, I need to translate it. Also, the user wants only the translation without any explanations. So the answer should be just "רבע מעגל".