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प्रश्न
The area of a circle is 1386 sq.cm; find its circumference.
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उत्तर
Area of circle = 1386 cm2
πr2 = 1386
`22/7r^2 = 1386`
`r^2 = 1386 xx 7/22`
`r^2 = 441`
r = `sqrt(441)`
r = 21 cm
circumference = `2pir`
= `2 xx 22/7 xx 21`
= 132 cm
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