Fractions with radicals in the denominator I'm working my way through the videos on the Khan Academy, and have a hit a road block. I can't understand why the following is true:
$$\frac{6}{\quad\frac{6\sqrt{85}}{85}\quad} = \sqrt{85}$$

No one seems to have posted the really simple way to do this yet:
$$
\frac{85}{\sqrt{85}} = \frac{\sqrt{85}\sqrt{85}}{\sqrt{85}}
$$
and then cancel the common factor.
