Question
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Answer (Detailed Solution Below)
Option 4 : 18 cm / 18 cm
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Detailed Solution
सही उत्तर 18 cm / 18 cm है।
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prepsnap.in • Part -AQuestion:
The diagonal of a rectangle is $\sqrt{41}$ cm and its area is $20\ \text{cm}^2$. What is its perimeter? / एक आयत का विकर्ण $\sqrt{41}$ cm है और क्षेत्रफल $20\ \text{cm}^2$ है। इसका परिमाप क्या है?
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14 cm / 14 cm
2.
15 cm / 15 cm
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16 cm / 16 cm
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18 cm / 18 cm
Correct Answer: 18 cm / 18 cm
$l^2 + b^2 = 41$ and $lb = 20$. Then $(l+b)^2 = 41 + 40 = 81$, so $l + b = 9$; perimeter $= 2 \times 9 = 18$ cm. (Trap: $(l-b)^2 = 1$ gives $l - b = 1$, but the question asks for the perimeter, not the sides.) / $l^2 + b^2 = 41$ तथा $lb = 20$। अतः $(l+b)^2 = 81$, $l + b = 9$; परिमाप $= 18$ cm।
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