So technically, we can write the square root of 4/5 as...
sqrt(4) / sqrt(5)
And then simplify it as thus...
2 / sqrt(5)
Now we need to move the square root to the numerator. We can do it like this.
( 2 / sqrt (5) ) * ( sqrt(5) / sqrt (5) )
= 2 * sqrt(5) / 5
If you were asked for the exact answer, then leave it as is. If asked for a rounded answer, then find the square root of 5 using a calculator, and go on from there.
So technically, we can write the square root of 4/5 as...
sqrt(4) / sqrt(5)
And then simplify it as thus...
2 / sqrt(5)
Now we need to move the square root to the numerator. We can do it like this.
( 2 / sqrt (5) ) * ( sqrt(5) / sqrt (5) )
= 2 * sqrt(5) / 5
If you were asked for the exact answer, then leave it as is. If asked for a rounded answer, then find the square root of 5 using a calculator, and go on from there.