Equal areas – Square vs rectangle (square side 40 cm, rectangle length 64 cm):\nA square has side 40 cm. A rectangle has the same area and length 64 cm. Find the perimeter of the rectangle.

Difficulty: Easy

Correct Answer: 178 cm

Explanation:


Introduction / Context:
Equal areas let us find the unknown breadth of the rectangle, after which perimeter is straightforward.


Given Data / Assumptions:

  • Square side = 40 cm ⇒ area = 40 * 40 = 1600 sq cm.
  • Rectangle length = 64 cm; breadth unknown.


Concept / Approach:
Set rectangle area = 1600 = 64 * breadth ⇒ breadth, then compute perimeter 2(L + B).


Step-by-Step Solution:

Breadth = 1600 / 64 = 25 cm.Perimeter = 2(64 + 25) = 2 * 89 = 178 cm.


Verification / Alternative check:
Area check: 64 * 25 = 1600 equals square area ✔️


Why Other Options Are Wrong:
187, 149, 194 arise from arithmetic slips or using 64 + 25 without doubling.


Common Pitfalls:
Forgetting perimeter doubles the sum of sides; mixing up area and perimeter formulas.


Final Answer:
178 cm

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