Multiple choice

Directions: In the following question, choose the correct alternative from the given options that will complete the series. 4, ?, 144, 400, 900, 1764

  1. 25

  2. 36

  3. 49

  4. 100
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The series is squares of even numbers: 2^2=4, 6^2=36, 12^2=144, 20^2=400, 30^2=900, 42^2=1764. The bases are 2, 6, 12, 20, 30, 42. Differences of bases: 4, 6, 8, 10, 12. The missing term is 6^2 = 36.

AI explanation

The terms in the series are all perfect squares. Taking the square roots gives the sequence 2, ?, 12, 20, 30, 42. The second differences of the roots are consistently 2. Extending this pattern backwards, the square root of the missing term must be 6. Squaring 6 gives the missing number 36.

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