Question 1203548
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The set of all students who have done that can be viewed as the set of all points a fixed distance from a given point, the fountain.<br>
The set of all points a fixed distance from a given point is a circle.<br>
ANSWER: circle<br>
Note that a circle consists of an infinite number of points, and there can't be an infinite number of students that are each 20 feet from the fountain, so the students don't actually form a circle.<br>
But of the given answer choices, clearly circle is the best.<br>