SAT Math Question of the Day

Math Category: Roots Level 2:

Q: 1 / √ 5

  1. 1/5
  2. 5
  3. √ 5
  4. 1 + √ 5
  5. √ 5  / 5

UNANSWERED.

The correct answer is E.

A: The answer is √ 5  / 5.

If you have a root in the bottom half of the fraction (the denominator) you have to multiply the top and bottom parts of the fraction by the root.

1   =   1 × √ 5   =   √ 5
√ 5 √ 5 × √ 5 5

The math term for this is to "rationalize the denominator".