Perimeter preserved — A square has area 64 sq cm. A circle with the same perimeter (circumference) is formed. Find its area.

Difficulty: Medium

Correct Answer: 256/π sq cm

Explanation:


Introduction / Context:
We map a fixed perimeter from a square to a circle. The square perimeter becomes the circle circumference. From the circumference we get the circle radius and hence its area.



Given Data / Assumptions:

  • Square area = 64 ⇒ side s = 8 cm
  • Square perimeter = 4s = 32 cm
  • Circle circumference = 32 = 2πr


Concept / Approach:
From 2πr = 32, get r = 16/π. Then circle area A = πr^2 = π * (16/π)^2 = 256/π sq cm.



Step-by-Step Solution:
r = 16/πA = π * (256/π^2) = 256/π sq cm



Verification / Alternative check:
Units consistent; the transformation uses perimeter equality only, not area equality.



Why Other Options Are Wrong:
Other fractions do not follow from r = 16/π. The exact symbolic form 256/π is required.



Common Pitfalls:
Using square area as circle area or using diameter instead of circumference to compute r.



Final Answer:
256/π sq cm

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