Definition of Terms
Circle: A circle is the locus or the set of all points equidistant from a fixed point called the centre.
Arc: A curved line that is part of the circumference of a circle.
Chord: A line segment within a circle that touches two points on the circle.
Circumference: The distance around the circle.
Diameter: The longest distance from one end of a circle to the other.
Centre: The fixed point from which all points on the circle are equidistant.
Pi (π): A number, approximately 3.141592, equal to the circumference divided by the diameter of any circle.
Radius: The distance from the centre of a circle to any point on it.
Sector: A region of a circle bounded by two radii and the arc between them, like a slice of pie.
Tangent: A line that is perpendicular to the radius and touches only one point on the circle.
Note: Diameter = 2 × Radius
Circumference of circle = π × diameter = 2π × radius