Circle
Circle
A 2D shape bounded by a set of points at an equal distance from a given point.
Properties
  1. It is 2D counterpart of a sphere.
  2. Center: The point equidistant from all points on the circle.
  3. Radius: The distance between any point on the circle and its center.
  4. Diameter: A chord that passes through the centre of the circle.
  5. Circumference: The perimeter or boundary of the circle.
  6. Chord: A straight line that joins any two points in a circle.
  7. Tangent: A line that touches the circumference of a circle at a single point.
  8. Secant: A line that cuts the circle at the two distinct points.
Area of Circle (A)
A = πr2
r: radius of the circle
π: pi is a constant = 3.1415 =
22 7
Diameter of Circle (d)
d = 2r
Circumference of Circle (C)
C = 2πr
Equation of Circle
Standard Form
(x − a)2 + (y − b)2 = r2
(a, b): Center of the circle
General Form
x2 + y2 + 2gx + 2fy + c = 0
Center of the circle: ( − g, − f)
Radius of the circle: g2 + f 2 − c