Question

The circumference of 2 circles are in ratio 1:3. Find the ratio of their areas.

Answer 1

Hi ☺☺

Solution :

The Circumference of two circle are in ratio 1:3

i.e., C1:C2 = 1:3

or C1/C2 = 1/3

=> 2π(r1)/2π(r2) = 1/3

=> r1/r2 = 1/3 ____(1)

Now ratio of their Area ,

A1/A2 = π(r1)²/π(r2)²

= (r1)²/(r2)²

= (r1/r2)²

= (1/3)² { from (1) }

= 1/9

Hence,

A1:A2 = 1:9

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