What is the Square Root of 18?

Instant answer with step-by-step solution

√18 = 4.2426406871
√18 = 4.2426406871
⚠ 18 is not a perfect square — result rounded to 10 significant figures

Step-by-step explanation

  1. We need to find √18 — a number that when multiplied by itself equals 18.
  2. 18 is not a perfect square. Its square root is irrational.
  3. It falls between √16 = 4 and √25 = 5.
  4. Using the formula √N = N^(1/2): √18 = 18^0.5 = 4.2426406871
  5. Verification: 4.2426406871 × 4.2426406871 ≈ 18 ✓ (rounded to 10 significant figures)

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Related calculations

Square root of 1818 square root√17 = 4.1231056256√19 = 4.3588989435√16 = 4√20 = 4.472135955√21 = 4.582575695√15 = 3.8729833462

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Also see

Square Root Laws Square Root Chart Easiest Method Negative Square Roots