That's called the 'radius'.
The length of a chord that contains the center of the circle
The diameter of a circle is twice its radius or its largest chord passing through the center of the circle.
A straight line from the center to the circumference.The distance from the center to any point on the circle
Circle
It is the circumcentre, the unique point from which you can draw a circle (the circumscribed circle) which passes through all three vertices.
"Circle". That "same distance" is the radius of the circle, and that "given point" is the center of the circle.
The length of a chord that contains the center of the circle
===> "circle", with center at the "single point" and radius of the "certain distance".
The diameter of a circle is twice its radius or its largest chord passing through the center of the circle.
The best tool to locate the center of a circle would be a compass. By placing the compass on the edge of the circle and drawing an arc, then repeating this process from another point on the circle, the intersection point of the arcs will give you the center of the circle.
A straight line from the center to the circumference.The distance from the center to any point on the circle
Circle
Circle
It is the circumcentre, the unique point from which you can draw a circle (the circumscribed circle) which passes through all three vertices.
The answer will depend on what the "certain distances" are for each point.
The major axis is the longest possible segment you can draw from one point on the ellipse ,through the center, and to the opposite point.
A Circle