Question

Draw any circle and mark

1. it's centre
2. a radius
3. a diameter
4. a sector
5. a segment
6. a point in its interior
7. a point in its exterior
8. an arc

Answer 1

A circle is a two-dimensional figure formed by a set of points that are at a constant or at a fixed distance (radius) from a fixed point (center) in the plane.

1. The centre of the circle is O.
2. The radius of the circle is OC.
3. The diameter of the circle is CA.
4. A sector of the circle is OBA.
5. A segment of the circle is DE. 
6. A point in the interior of the circle is P.
7. A point in the exterior of the circle is Q.
8. An arc of the circle is AB.