**(a) In the figure (i) given below, the area enclosed between the concentric circles is 770 cm**^{2}. Given that the radius of the outer circle is 21 cm, calculate the radius of the inner circle.

**(b) In the figure (ii) given below, the area enclosed between the circumferences of two concentric circles is 346.5 cm**^{2}. The circumference of the inner circle is 88 cm. Calculate the radius of the outer circle.

^{2}. Given that the radius of the outer circle is 21 cm, calculate the radius of the inner circle.

^{2}. The circumference of the inner circle is 88 cm. Calculate the radius of the outer circle.

**Solution:**

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