Parts of a circle

Key notes:

Parts of a Circle

1. Circle: A circle is a closed shape where all points are equidistant from a fixed point called the center.
2. Center: The center is the point inside the circle that is equidistant from all points on the circumference.
3. Radius: The radius is the distance from the center of the circle to any point on the circumference. It is half the diameter.
   • Formula: Radius (r) = Diameter (d) / 2
4. Diameter: The diameter is a straight line that passes through the center and connects two points on the circumference. It is twice the length of the radius.
   • Formula: Diameter (d) = 2 × Radius (r)
5. Circumference: The circumference is the distance around the circle. It can be calculated using the formula:
   • Formula: Circumference (C) = π × Diameter (d) or C = 2 × π × Radius (r)
6. Chord: A chord is a line segment whose endpoints lie on the circle. It does not necessarily pass through the center.
7. Arc: An arc is a part of the circumference of a circle. It can be measured in degrees.
8. Sector: A sector is a region of a circle bounded by two radii and the arc between them. It looks like a “slice” of the circle.
9. Segment: A segment is a region of a circle that is bounded by a chord and the arc connecting the endpoints of the chord.
10. Tangent: A tangent is a line that touches the circle at exactly one point. It is perpendicular to the radius drawn to that point.
11. Secant: A secant is a line that intersects the circle at two points.