Circle- The locus of all points in a plane equidistance from a given point.

Center- Given point/how you name the circle.

Circumference- distance around the circle.

Chord- segment w/ endpoints on the circle.

Diameter- Chord through the center.

Radius- segment w/ endpoints on the circle and center. equals 1/2 of the diameter.

Pi= Circumference/ diameter

Circumference= Pi(diameter)