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If three circles of radius a each, are drawn such that each touches the other two, prove that the area included between them is equal to 4/25 a^2. [Take sqrt(3) = 1.73 and π = 3.14.]

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Question

If three circles of radius a each, are drawn such that each touches the other two, prove that the area included between them is equal to `4/25 a^2`. [Take `sqrt(3) = 1.73` and π = 3.14.]

Theorem
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Solution

When three circles touch each other, their centres form an equilateral triangle, with each side being 2a.

Area of the triangle`=sqrt(3)/4xx2"a"xx2"a" = sqrt(3)"a"^2`

Total area of the three sectors of circles `=3xx60/360xx22/7xx"a"^2 = 1/2xx22/7 "a"^2 = 11/7"a" ^2`

Area of the region between the circles = Area of the triangle - Area of three sectors

`=(sqrt(3)-11/7)"a"^2`

= (1.73 - 1.57)a2

= 0.16 a2

=  0.16 a2

`=4/25"a"^2 `

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Chapter 16: Area of Circle, Sector and Segment - EXERCISE 16A [Page 733]

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R.S. Aggarwal Mathematics [English] Class 10
Chapter 16 Area of Circle, Sector and Segment
EXERCISE 16A | Q 40. | Page 733
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