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प्रश्न
Find the area of a circle whose circumference is 22 cm.
उत्तर
Let r be the radius of the circle, then circumference = 2πr
⇒ 2πr = 22 cm
⇒ r = `22/(2π) = (22 xx 7)/(2 xx 22) = 7/2 "cm"`
∴ Area of circle = πr2
∴ Area of circle = `22/7 xx 7/2 xx 7/2 "cm"^2 = 77/2 "cm"^2`
∴ Area of circle = 38.5 cm2.
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