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Ab is a Chord of a Circle with Centre O and Radius 4 Cm. Ab is of Length 4 Cm. Find the Area of the Sector of the Circle Formed by Chord Ab. - Mathematics

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Question

AB is a chord of a circle with centre O and radius 4 cm. AB is of length 4 cm. Find the area of the sector of the circle formed by chord AB.

Sum

Solution

We have to find the area of the sector AOB formed by the chord AB. 

We have  `OA=4 cm and AB=4 cm. So,`

`AL=(AB)/2 cm` 

`= 4/2 cm` 

`= 2 cm` 

Let ∠AOB=2θ. then, 

`∠AOL=∠BOL` 

=θ 

In ΔOLA, We have

`sin θ=(AL)/(OA)`

`= 2/4`

`=1/2` 

`θ = sin^-1  1/2` 

`= 30°`

Hence,  `∠AOB=60°`

Now, using the value of`∠AOB`  and r we will find the area of sector AOB,

`A=θ/(360°) xx pir^2` 

=` (60°)/(360°)xx pixx4xx4 cm^2`

`=(8pi)/3 cm^2`

 

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Chapter 13: Areas Related to Circles - Exercise 13.2 [Page 25]

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RD Sharma Mathematics [English] Class 10
Chapter 13 Areas Related to Circles
Exercise 13.2 | Q 24 | Page 25

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