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प्रश्न
The area of a circle is 49 π cm2. Its circumference is:
विकल्प
7 π cm
14 π cm
21 π cm
28 π cm
उत्तर
14π cm
Explanation:
Let the radius be r cm.
We know:
Area of a circle
Thus, we have;
πr2 = 49π
⇒ r2 = 49
`⇒ r = sqrt(49)`
⇒ r = 7
Now,
Circumference of the circle = 2πr
`= (2xx22/7xx7) "cm"`
= 14π cm
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