3. What is a circle? A circle is a locus of a point in a plane which moves such that its distance from a fixed point in the same plane remains constant . The fixed point is called the centre of the circle and the fixed distance is called the radius. O P Here O is the centre and OP is the radius.
4. The bottom and top of a bucket is usually a circle. A playing drum is circular. A clock is usually circular. The top of the table shown below is a circle. Where do you find circles? Look around you! There are circles everywhere!
5. Basic terms related to a circle.... Centre & radius Chord Minor arc & major arc Diameter Minor segment & major segment Central angle Circumference Circular region Sector
6. A line segment joining any two points on the circle is called a chord of a circle. O Here AB is a chord . A B Chord
7. A chord passing through the centre of the circle is called the diameter . It is the longest chord. A B C D Here AB is diameter. Diameter
8. The circumference of a circle is the distance around the outside of it. Here light blue portion is circular region. Circumference
9. A circle along with its interior is called the circular region. Circular region Circular region
10. Any two points of the circle divide the circle into two parts called the arcs . The smaller part is called the minor arc and the larger part is called the major arc. In case the two parts are equal each one of them is called a semicircle. . Horizontal lines region is the minor segment and the remaining circular region is the major segment Minor arc , Major arc
11. A chord divides a circular region into two parts called the segments of the circular region. The smaller segment is called as minor segment and the larger segment is called as the major segment. Horizontal lines region is the minor segment and the remaining circular region is the major segment Minor Segment, Major Segment
12. The angle subtended by an arc at the centre of the circle is called the central angle. A B Central angle
13. A B Corresponding to a given arc, the region bounded by the two radii and the arc itself. Sector
