How do do you rationalize the square root of 5 divided by the square root of 8?

1 Answer
Sep 8, 2015

sqrt5/sqrt8 = color(green)(sqrt10/4

Explanation:

Rationalisation is simply expressing a fraction in a form that has a rational denominator .

sqrt5/sqrt8 is the fraction that we have been given

The denominator sqrt 8 is irrational. To convert it to a rational number, we can multiply the numerator and the denominator of the fraction by sqrt2

sqrt5/sqrt8 = (sqrt5*sqrt2)/(sqrt8*sqrt2)

We know that color(blue)(sqrta*sqrtb = sqrt(ab)
Hence (sqrt5*sqrt2)/(sqrt8*sqrt2) = sqrt(5*2)/sqrt(8*2) = sqrt 10/sqrt16 = sqrt10/4

Now the denominator 4 is rational. Hence we can be sure that we have rationalised the denominator

sqrt5/sqrt8 = color(green)(sqrt10/4