Difficulty: Medium
Correct Answer: 178 cm
Explanation:
Introduction / Context:This problem tests the relationship between area and perimeter across different shapes. You are told that a square and a rectangle have the same area. The square’s side gives you its area directly. Then, using the rectangle’s length, you can compute its breadth from area = length * breadth. Finally, apply the rectangle perimeter formula 2 * (length + breadth).
Given Data / Assumptions:
Concept / Approach:Compute square area. Use it as rectangle area. Find breadth = area / length. Then compute perimeter from length and breadth.
Step-by-Step Solution:
Step 1: Area of square = 40 * 40 = 1600 sq cm Step 2: Rectangle area = 1600 sq cm (equal areas) Step 3: Breadth of rectangle = area / length = 1600 / 64 = 25 cm Step 4: Perimeter = 2 * (64 + 25) = 2 * 89 = 178 cmVerification / Alternative check:Check area consistency: 64 * 25 = 1600 sq cm, which matches the square’s area. Since the area match is correct, the perimeter calculation using those dimensions is valid.
Why Other Options Are Wrong:
187 cm and 194 cm: would imply a larger breadth than 25 cm for the same length and area. 149 cm: would imply a smaller breadth, which would reduce area below 1600 sq cm. 168 cm: corresponds to (64 + 20) * 2, but breadth 20 would give area 1280, not 1600.Common Pitfalls:Common mistakes include using perimeter formulas for area, mixing up square side with rectangle length, or calculating breadth as 64/1600 instead of 1600/64. Also, always keep units consistent in cm throughout the calculation.
Final Answer:178 cm
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