A sphere
Surface of a sphere
A sphere would fit the given description.
It is a round plane figure whose boundary (the circumference) consists of points equidistant from a fixed point (the center).
In a convex figure, if you pick any two points, the points between them are also a part of the figure.
A circle or a sphere
It depends on how many dimensions you are asking about. If you are talking about a 2-dimensional figure then it would be a circle. The definition of a circle is the collection of points that are equidistant from the center. If you are talking about a 3-dimensional figure, then it would be a sphere. The definition of a sphere is the collection of points in three dimensions that are equidistant from the center.
if it's a circle, all points are equidistant from the center.
A circle.
A sphere
a sphere
vertices
A circle or sphere.
A rounded figure that has all surface points equidistant from the center is a sphere. A common object that is a sphere is a tennis ball.
A circle or a sphere
A sphere has all points on it equal distanced from its centre.
A circle.