Answer:
Radius
Explanation:
The center of a circle is a point that's the same distance from any point on the circle itself. This distance is called the radius of the circle, or r for short. And any line segment from one point on the circle through the center to another point on the circle is called a diameter, or d for short.
the diameter of any circle is made up of one radius plus another radius — that is, two radii. This concept gives you the following handy formula d=2xr