Explanation

A circle is the set of all points in a plane that are equidistant from a fixed point, called the center.

Key points:

• Center: $(h,k)$

• Radius: r

• General shape: round and symmetric

• Distance from center to any point on circle = radius

Graphing a circle: Plot the center, then draw points at a distance $r$ in all directions, then connect smoothly.

Example: Center (2,3), radius = 4 → every point satisfies distance 4 from (2,3).