Grade 8 Math · The Number System

Compare irrational and rational numbers

Compare irrational and rational numbers.

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What you’ll learn

Compare irrational and rational numbers.

Key idea

For nonnegative values, comparing squares preserves order; an approximation is not an exact equality.

For nonnegative values square order is preserved; irrational does not mean larger.

Worked example

Classify examples and non-examples for the concept 'Compare irrational and rational numbers'.

Compare √2 with 1.6 by exact squares. Choose the relation with evidence.

  1. Both √2 and 1.6 are positive; compare their squares 2 and 64/25.
  2. Since 2<64/25, √2<1.6; neither radical notation nor irrationality alone sets order.

Answer: √2<1.6 — 2<1.6²=64/25, and both quantities are positive.

Quick Check

Classify examples and non-examples for the concept 'Compare irrational and rational numbers'.

Compare √2 with 4.1 by exact squares. Choose the relation with evidence.

Choose one answer

Show a hint

Use exact magnitude comparisons rather than the type of notation.