# How do you simplify #4 sqrt (81/16)#?

##### 1 Answer

Aug 7, 2016

#### Explanation:

If you recognise 81 and 16 as being 4th powers, the answer is easy to write down as

Otherwise write each number as the product of its prime factors:

The 4th root is easy to find if you remember it is the square root of a square root.

81 and 16 are both perfect squares, but their square roots are also squares.