Introduction and Important theorem of circle

I am a circle!!!

Circle- The locus of points which is equidistant from the center is called circle. 

Chord: Any line segment whose end points lie on the circle is called a chord

Diameter: Diameter is the longest chord of the circle. It is that chord, which passes through the centre. A diameter is twice the radius of a circle.

Secant: A line segment that intersects a circle at two points is called a secant. 

Tangent: A line that touches the circle at one and only one point is called a tangent

Segment: A circle is divided into two parts by a chord, which are called segments

Arc: -a part of a curve, especially a part of the circumference of a circle.

Sector: The part of the circle which is bounded by an arc and two radius is called sector.

Congruent Circles: Two circles having equal radii, are called congruent circles


                                                       Theorem of circle

1. Equal chords of a circle subtend equal angles at the centre.
2. If the angles subtended by the chords of a circle at the centre are equal, then the chords are equal.
3. The perpendicular from the centre of a circle to a chord bisects the chord.
4. The line drawn through the centre of a circle to bisect a chord is perpendicular to the chord.
5. There is one and only one circle passing through three given non-collinear points.
6. Equal chords of a circle (or of congruent circles) are equidistant from the centre (or centres).
7. Chords equidistant from the centre of a circle are equal in length.
8.The angle subtended by an arc at the centre is double the angle subtended by it at any point on the remaining part of the circle.
9. Angles in the same segment of a circle are equal.