In this page sector of a circle we are going to see the definition of sector in a circle and its classification.
Definition of a Sector:
A part of the interior of a circle enclosed by an arc and two radii is called a sector of a given circle.
Consider a sector of a circle whose central angle measure. ∠AOB = θ and radius "r" and length of arc AB is known as L.
There are two types of sectors. Those are
(i) Major sector
(ii) Minor sector
A larger part occupied by two radii is called the major sector. A major sector has central angle which is more than 180°.
A smaller part occupied by two radii is called the minor sector. A minor sector has central angle which is less than 180°.
A part occupied by two radii with central angle 90° is called quadrant. In other words we can define quadrant as one fourth of the circle.
A part occupied by two radii with central angle 180° is called the semicircle.
Now we are going to have a set of question in which you have to choose which is major sector and which is minor sector.
Identify the major sector in the below diagram.
Here ACB is the major part of the circle so it is called a major sector.
Identify the minor sector in the below diagram.
Here AOC is the minor part of the circle so it is called a minor sector.
If the circumference of a circle is 8 units and arc length of major sector is 5 units then find the length of minor sector.
(A) 3 units
(B) 7 units
(C) 5 units
The length of minor sector is 3 units. Because circumference means length of the circle by subtracting the length of the major sector from the circumference we can get the length of minor sector.