Circles - Self Learning Module

Circles

Circles

​Sector of a Circle

The portion (or part) of the circular region enclosed by two radii and the corresponding arc is called a sector of the circle.

​Sector of a Circle

Note:

• The region OAXB is a sector of the circle with centre O. Angle AOB is called the angle of the sector.

• The region OAYB is also a sector of the circle. OAXB is called the minor sector and OAYB is called the major sector.

• Angle of the major sector is 360° – Angle AOB.

Segment of a Circle

The portion (or part) of the circular region enclosed between a chord and the corresponding arc is called a segment of the circle.

Segment of a Circle

• AB is a chord of the circle with centre O. Region ACB is a segment of the circle.

• Also note that region ADB is another segment of the circle formed by the chord AB.

• ACB is called the minor segment and ADB is called the major segment.

Multiple Choice

What is the diameter of a circle with radius 15m?

• 15 m

• 30 m

• 7.5 m

• 225 m

Multiple Choice

A sector is enclosed by ________radii

• 2

• 0

• Infinite

• 1

Multiple Choice

Is a Semicircle a Segment?

• Yes

• No

Area of a circle

Multiple Choice

The angle around the centre of a circle is ______

• $$360\degree$$

• $$180\degree$$

• $$0\degree$$

• $$90\degree$$

Multiple Choice

Sector is a/the _____of the circle

• part

• circumference

• whole

• none of these

Multiple Choice

Circumference of a circle is 88 cm. Find its area.

• 44 sq.cm

• 1232 sq.cm

• 14 sq. cm

• 616 sq.cm