sqrt{3} = 1.732050807568877\) ... \(\pi = 3.14159\) ... Roots that cannot be written as exact decimals are called surds. Leaving an answer in surd form means the answer is exact. This square has ...

Rationalising an expression means getting rid of any surds from the bottom (denominator) of fractions. Usually when you are asked to simplify an expression it means you should also rationalise it.