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Two concentric circles have areas in the ratio 1 : 4. The ratio of their radii is
A2 : 1
B1 : 4
C1 : 8
D1 : 2
Answer & Solution
Correct answer: D. 1 : 2
1. Area ratio = (r1/r2) squared = 1/4.
2. Square root: r1/r2 = 1/2.
3. Hence 1 : 2.
_Source: NCERT Class 10 Mathematics, Ch 11 "Areas Related to Circles", §11.2_
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