
Geometry  Arcs & Circles 
Here are formulas for
some of the most commonly used arcs and circles. Equations for area and circumference are provided.
K = area R = radius D = diameter C = circumference θ = central angle (radians)
Sector
and Segment

Parabolic
Segment
K (right segment)
K
(oblique segment)
, where T is the
area of the triangle with the base along the chord of the segment and with opposite vertex at the
point on the parabola at which the tangent to the parabola is parallel to the chord of the segment. 
Source: CRC Standard Math Tables, 1987



