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The area of a circle is proportional to the square of its radius. A small circle of radius 3 cm is drawn within a larger circle of radius 5 cm. Find the ratio of the area of the annular zone to the area of the larger circle. (Area of the annular zone is the difference between the area of the larger circle and that of the smaller circle).
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- 9 : 16
- 9 : 25
- 16 : 25
- 16 : 27
- 9 : 16
Correct Option: C
Using Rule 14,
Area of circle = kr²
Area of shaded region
= k (5² – 3²) = 16π sq. units
Area of larger circle = k × 5²
= 25p sq. units
∴ Required ratio = 16 : 25
