Let's fly back again to the days of dinosaurs and no calculators!
If math geeks had to calculate a decimal for something like
things got really ugly.
They'd have to use a table to get the value for ... Then, they'd have to do the long division by hand:
So, it was a LOT easier for them if there wasn't a radical in the denominator.
They created a fun little game called "rationalizing the denominator."
Here's how it goes:
Multiply by a magic 1.