Sector
Definition Of Sector
The area between an arc and two radii of a circle is called Sector.
More About Sector
Sector can also be referred as Wedge.
Asector is the region enclosed by two radii and an arc. The two radii divide the circle into two sectors called a major sector and a minor sector.
A minor sector has an angle at the centre of the circle of less than 180°.
A major sector has an angle at the centre of the circle of more than 180°.
Area of the sector of a circle of radius r is given as 1/2 r2θ.
Video Examples: Sectors and Cones - GCSE Maths Revision
Example of Sector
Solved Example on Sector
Ques: Find the area of the sector AOB.
Choices:
A. 3.25p cm2
B. 4.5 cm2
C. 6.75p cm2
D. 3p cm2
Correct Answer: C
Solution:
Step 1: Area of the sector of a circle = 1/5r2? [Formula.]
Step 2: θ = 120° = 120 × π / 180 = 2π/3 radians [Convert degrees to radians.]
Step 3: = 1/2 × (4.5)2 × 2π/3 [Substitute the values.]
Step 4: = 6.75π [Simplify.]
Step 5: So, the area of the given sector is 6.75π cm2