Farsana . S

BEd. Mathematics

Register number : 13386003

St Thomas Training College.

CIRCLES

o

radius

diameter

A circle has a centre.

The line joining any two points in a circle is the

chord.

The longest chord which passes through the

centre of the circle is diameter.

Radius is half the diameter.

PERIMETER OF A CIRCLE

perimeter = 2 r ; where ≈ 3.14

r = radius of the circle.

AREA OF A CIRCLE

Area of a circle = r² ;where r is the radius

ARC LENGTH

The length of an arc of a circle is that

part of the perimeter of the circle as the central

angle is 360°.

Arc length = x

360 ; where r is the radius

x is the central angle

2 r

SECTOR

It is a part of circle extending to the centre.

AREA OF A SECTOR