Okay, the user wants me to translate "quarter-circle" into Portuguese. Let me think. The term "quarter-circle" refers to a quarter of a circle, which is 90 degrees. In Portuguese, "quarter" is "quarto" and "circle" is "círculo". So, "quarter-circle" would be "quarto de círculo". But I should check if there's a more common term. Maybe "quarto de círculo" is correct, but sometimes technical terms might have specific translations. However, since the user didn't specify any context, the direct translation should be fine. Also, the user mentioned that if the content is already in Portuguese, leave it as is. Since the original is in English, I need to translate it. So the answer should be "quarto de círculo".