Classification – Perfect squares: pick the odd one out. Three numbers are perfect squares; one is not a perfect square. Which number is different? Options: 144, 169, 256, 288.

Introduction / Context:
Square numbers are a staple of numerical classification. Identifying which figures are exact squares separates the majority from the exception.

Given Data / Assumptions:

• 144 = 12^2, 169 = 13^2, 256 = 16^2.
• 288 is between 16^2=256 and 17^2=289.

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

Step-by-Step Solution:
Check 144 → 12 * 12 → perfect square.Check 169 → 13 * 13 → perfect square.Check 256 → 16 * 16 → perfect square.Check 288 → 16^2=256 and 17^2=289; 288 is not an exact square.

Verification / Alternative check:
Prime factors: 288 = 2^5 * 3^2 includes an odd exponent (5), hence not a perfect square.

Why Other Options Are Wrong:
144, 169, 256: Each is an exact square and belongs to the majority.

Common Pitfalls:
Confusing 289 (17^2) with 288; a quick boundary check prevents this error.

Final Answer:
288