Question:medium

If the perimeter of a circle is equal to that of a square, then the ratio of their areas is :

Show Hint

For any given perimeter, a circle always encloses the maximum area compared to any polygon.
This means the ratio of circle area to square area must be greater than 1.
Among the options, only (A) 22:7 and (D) 14:11 are greater than 1.
Since 22:7 is much too large, 14:11 is the correct geometric ratio.
  • 22 : 7
  • 11 : 14
  • 7 : 22
  • 14 : 11
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Pick a convenient actual radius rather than working symbolically.
Since we will use $\pi = \frac{22}{7}$, let the circle's radius be $r = 7$ cm, a multiple of 7 keeps the numbers clean.
Step 2: Find the circle's circumference, and match the square's perimeter to it. \[ C = 2 \times \frac{22}{7} \times 7 = 44 \text{ cm} \] Since the square has the same perimeter, its side is \[ a = \frac{44}{4} = 11 \text{ cm} \]
Step 3: Work out both areas with these actual numbers. \[ \text{Area of circle} = \frac{22}{7} \times 7^2 = \frac{22}{7} \times 49 = 154 \text{ cm}^2 \] \[ \text{Area of square} = 11^2 = 121 \text{ cm}^2 \]
Step 4: Write the ratio in simplest form. \[ 154 : 121 = 14 : 11 \] \[ \boxed{14 : 11} \]
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