Radius of outer circle (r) = 19 m
∴ Circumference of outer circle = 2πr = 2 x 3.14 x 19
= 119.32 m
Now radius of inner circle (r’) = 19 – 10 = 9 m
∴ Circumference of inner circle = 2πr’ = 2 x 3.14 x 9
= 56.52 m
Therefore, the circumferences of inner and outer circles are 56.52 m and 119.32 m
respectively.

Class 7 Maths Chapter 11 Exercise 11.3

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