How do you write square root of 72 in algebra?

You would have the square root symbol (called a radical) over the number 72. But if you mean to simplify it, you can keep in mind that 9 x 3 = 72 and the square root of 9 is 3, so then your answer would be

3(radical)3

Hope that's not too confusing!

Your maths is very weak try yourself this would improve your skills don't depend on others