Circle
Tangent - A Line that intersects a circle at only 1 point
Secant - A line that intersects a circle at 2 points
Chord - A line where both points are on the circle (Segment)
Diameter - Chord that goes through the center (2 Radius)
Arc - Length of 2 Points on circle (Minor Arc and Major Arc)
Circumference - Distance around the circle
Diameter = 2 x Radius
Ratio of Circumference to diameter
C/D = 3.14159 (Pi)
Circumference = (2 x Pi x R) or (Pi X D)
Arc Measure (Degrees) = The Minor Arc Angle. Measure of the centre angle that intercepts the circle
Radians
Arc length is the same as Radius
2 Pi radians = 360
1 Radian = 180 / Pi
1 Degree = Pi / 180