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90 = 2 x 3 x 3 x 5. Since 2 and 5 are unpaired, 90 is:
AA perfect cube
BA prime number
CNot a perfect square
DA perfect square
Answer & Solution
Correct answer: C. Not a perfect square
1. Only the 3s form a pair.
2. 2 and 5 stand alone.
3. So 90 is not a perfect square.
_Source: NCERT Class 8 Mathematics, Chapter 6, Squares and Square Roots._
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