Classification – Perfect squares: three numbers are exact squares; one is not a perfect square. Which is the odd one out? Options: 49, 36, 65, 100.

Introduction / Context:
Square recognition is foundational in numerical classification. A single non-square among well-known squares is the intended outlier.

Given Data / Assumptions:

• 49 = 7^2.
• 36 = 6^2.
• 100 = 10^2.
• 65 is between 8^2=64 and 9^2=81 → not a square.

Concept / Approach:
Check each value against nearby integer squares or factorization to confirm square status.

Step-by-Step Solution:
Verify 49, 36, 100 as squares.Recognize 65 is not an exact square.

Verification / Alternative check:
Prime factorization: 65 = 5 * 13 contains no repeated prime factors, hence not a square.

Why Other Options Are Wrong:
49/36/100: Each is a perfect square and forms the majority class.

Common Pitfalls:
Confusing 64 (square) with 65 due to adjacency.

Final Answer:
65