Each circle comprises:
- radius, which is the distance from the center to any point on the circle;
- chord, which is a line joining two points on the circle;
- diameter, which is longest chord, the one goes through the center;
- circumference, which is the boundary of the circle. It is also the distance you would have to travel if you walked all the way around the circle;
- tangent, which is a line that touches the circle at only one point;
- sector, which is the region inside the circle between two radii;
- segment, which is the region between a chord and the circumference.