Between a square of perimeter 44 cm and a circle of circumference 44 cm, which figure has larger area and by how much?
Aptitude
Area
Difficulty: Easy
Choose an option
-
ABoth have equal area
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BSquare, 33 cm²
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CCircle, 33 cm²
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DSquare, 495 cm²
Answer
Correct Answer: Circle, 33 cm²
Explanation
### Concept & Isoperimetric Inequality
For a given fixed perimeter, a circle will always enclose the maximum possible area compared to any other standard polygon (like a square or triangle).
$$\text{Area}_{\text{square}} = s^2$$
$$\text{Area}_{\text{circle}} = \pi r^2$$
### Step-by-Step Solution
* **Analyze the Square:**
Perimeter = $4s = 44$ cm $\Rightarrow s = 11$ cm.
Area of Square = $s^2 = 11^2 = 121$ cm².
* **Analyze the Circle:**
Circumference = $2\pi r = 44$ cm.
$2 \times \frac{22}{7} \times r = 44 \Rightarrow \frac{44}{7} \times r = 44 \Rightarrow r = 7$ cm.
Area of Circle = $\pi r^2 = \frac{22}{7} \times 7^2 = 22 \times 7 = 154$ cm².
* **Compare the Areas:**
The circle has the larger area: $154$ cm² vs $121$ cm².
Difference = $154 - 121 = 33$ cm².
### Exam Strategy & Shortcut
Memorize standard integer pairs for speed: A circle with radius $r=7$ has circumference $C=44$ and Area $A=154$. A square with perimeter $P=44$ has side $s=11$ and Area $A=121$. Subtracting them instantly yields 33.
### Common Pitfall
Assuming that figures with equal perimeters must logically hold equal areas, prompting a rapid but incorrect selection of option (a).
### Final Answer
Therefore, the correct answer is **Circle, 33 cm²**.