select any irrational number and turn it into a rational number?

Answer 1

If you take any irrational and truncate it
after finitely many decimal places, it becomes
rational, because it is now a terminating decimal.
Example: √2 = 1.4142135...
If I write only the first 3 decimal places, we
have 1.414, which is rational and a rational
approximation to √2.

Answer 2

More detail needed in this question.

There are irrational numbers which are not the roots of rational functions and hence you can not just square it or similar to get to a rational number.

A very simple answer would be the ceiling function which rounds any number up to a whole number.

Answer 3

Dividing is faster.
Or subtracting is much faster.

Also, can try:
multiply by 0
raise to the power of 0
floor it
ceiling of it
rounding it up/down

Finally, I think truncating it is a quick/easy/useful way as the result is approximately the original number.

Answer 4

Sqrt(3) is irrational

But Sqrt(3) * Sqrt(3) = 3 which is rational

Answer 5

that will only happen if you multiply it by itself if it is an even root.
root2 * root 2 = 2
root(a) *root(a) = a
if it is a cube root it is a little more difficult,
i would look at www.purplemath.com as a reference