Perfect Math 10 ( 2074BS)

20. Circle OA

Terms Related to Circle

A circle is the locus traced out by a moving point which is equidistant from
a fixed point. The fixed point is called the centre and the fixed distance is called
the radius of the circle. In the figure, O is the centre and OA is its radius. Here
are some different parts of a circle.

S.No. Part Name Definition Figure

1. Segment A region enclosed by an arc and a chord O Major
2. Sector C segment
3. Concyclic points of a circle. ABC is a segment. A
B Minor

segment

A region enclosed by any two radii and an O Major Geometry
arc of a circle . OAB is a sector of the sector
circle. AB Minor
P sector
Four or more than four points through
which a circle may be drawn. P, Q, R, S Q T
and T are concyclic points. O S

R

4. Chord A line segment joining any two points of O
the circumference. AB is a chord. A
B

5. Cyclic quadrilateral The quadrilateral having its vertices Q D
concyclic. ABCD is a cyclic quadrilateral. P
A
O

BC

6. Central angle The angle at the centre of the cirlce. ®AOB O
is a central angle. AB

Circle 197