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The radius of a circle is 5 m. Find the circumference of the circle whose area is 49 times the area of the given circle.

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#### Solution

Area of the circle having radius 5 m is

A = π × (5)^{2 }

= 25 π m^{2}

Let r be the radius of the circle whose area is 49 times of the given circle.

π r^{2} = 49 × (π x 5^{2})

r^{2} = (7 × 5)^{2}

r = 35 m

Hence circumference of the circle

circumference = 2πr

circumference = 2 × `22/7`× 35

circumference = 220 m

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