For 10 points, name this conic section with zero eccentricity, in which all points on it are equidistant from its center.
This figure is homeomorphic to the one-point compactification of the real numbers. One of these figures that intersects the midpoints of all the sides and the feet of all the altitudes of a triangle is called the "nine-point" one. Because the roots of unity fall on this figure, it can be parametrized by the sine and cosine functions. This figure maximizes the ratio of area to perimeter. In polar coordinates, it can be defined by the equation r equals a constant. The ability to draw one of these with any center and any size was one of Euclid's postulates. For 10 points, name this conic section with zero eccentricity, in which all points on it are equidistant from its center.
This figure is homeomorphic to the one-point compactification of the real numbers.
circle [accept nine-point circle] &lt;BH/AS&gt;