Mathematics

Find the radius and area of a circle if its circumference is 18π cm.

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Answer

Let radius = r cm.

By formula,

Circumference = 2πr

⇒ 2πr = 18π

⇒ 2r = 18

⇒ r = 9 cm.

Area of circle = πr²

= $\dfrac{22}{7} \times 9^2 = \dfrac{22 \times 81}{7}$

= $\dfrac{1782}{7} = 254\dfrac{4}{7}$ cm².

Hence, radius = 9 cm and area = $254\dfrac{4}{7}$ cm².

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