SAT Math Question of the Day

Math Category: Roots Level 2:

Q: 1 / √ 7

  1. √ 7
  2. 1/7
  3. 7
  4. √ 7  / 7
  5. 7 + √ 1

UNANSWERED.

The correct answer is D.

A: The answer is √ 7  / 7.

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 × √ 7   =   √ 7
√ 7 √ 7 × √ 7 7

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