Gujarat BoardEnglish MediumSTD 8MATHSCube and Cube Roots1 Mark
MCQ
Which among the following is a perfect cube?
A
$400$
✓
$15625$
C
$243$
D
$9000$
✓
Answer
Correct option: B.
$15625$
$400 = 2 \times 2 \times 2 \times 2 \times 5 \times 5; 2 \times 5 \times 5$ remains after grouping into triplets.Therefore, it is not a perfect square.
$15625 = 5 \times 5 \times 5 \times 5 \times 5 \times 5$ In this factorization, nothing remains after grouping $S'$s in triplets. Therefore, it is a perfect square.
$243 = 3 \times 3 \times 3 \times 3 \times 3$ In this factorization $3 \times 3$ remains after grouping $3'$ in triplets. Hence, it is not a perfect square.
$9000 = 3 \times 3 \times 2 \times 2 \times 2 \times 5 \times 5 \times 5$ In this factorization $3 \times 3$ remains after groping $5's$ and $2's$ in triplets.
Hence, it is not a perfect. Square.
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