GCSE Maths (AQA)

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Rationalising the Denominator

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Number Structure and Calculation

Rationalising the Denominator

4:37 Surd Problems
Spec N8 A4
Previous Expanding Double Brackets with Surds Next Advanced Rationalising the Denominator
  • A fraction with an irrational denominator can be rewritten with a rational denominator
  • An irrational number cannot be represented as a fraction with integer numerator and denominator
  • The technique to rationalize the denominator is to multiply the numerator and denominator by the denominator of the original fraction
  • Multiplying the numerator and denominator by the same number does not change the value of the fraction
  • The square root of a non-perfect square is an example of an irrational number
  • The rule for multiplying square roots with coefficients is to multiply the coefficients together and multiply the numbers inside the square roots together
  • The rule for multiplying square roots is root A times root B equals the square root of A times B
  • The square root of a product is equal to the square roots of its factors multiplied together
  • Common factors in the numerator and denominator can be cancelled to simplify the fraction

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