If the area of a circle is 38.5m 2, then its circumference will be _____? - IQ786

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If the area of a circle is 38.5m 2, then its circumference will be _____?

If the area of a circle is 38.5m 2, then its circumference will be _____?

22 m

2.2 m

38.5 m

35 m

Explanation

Area of a circle $= π r^{2}$
$∴ 38.5 = π r^{2}$
$∴ \frac{2 2}{7} \times r^{2} = 38.5$
$\Rightarrow r^{2} = 38.5 \times \frac{7}{2 2}$
$\Rightarrow r^{2} = 12.25 \Rightarrow r = 12.25$
$∴$ $r = 3.5$
Now, Circumference of circle $= 2 π r$
$∴$ Circumference of circle $= 2 \times \frac{2 2}{7} \times \frac{3 5}{1 0}$
$∴$ Circumference of circle $= 22 m$ Area of a circle $= π r$