1.

The area of circle is 100 times the area of another circle. What is the ratio of their circumferences?

Answer»

Let the area of the circles be A1 and A2 and their circumference be c1 and crespectively.

According to the question it is clear that A1 = 100 A2

⇒ π (r1)2 = 100 × π (r2)2

⇒ r1 = 10 r2

⇒ r1/r2 = 10/1 … (i)

Finding the ratios of the circumference;

C1: C2 = 2πr1:  2πr2

C1/C2 = (2πr1)/ (2πr2)

C1/C2 = r1/r2

Putting the value of r1/rfrom equation (i)

C1/C2 = 10/1

C1: C2 = 10: 1

Hence, the ratio of their circumferences is 10: 1.



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