example the rational approximation of pi is 3.14

so a rational approximation is shortening a really long number so it can be written out

3.14159 is rational. However, it is often used as an approximation for π, which is irrational. It is important to recognise that the rational number, 3.14159, is only an approximation for π.

The square root of six is irrational. Do you mean a rational approximation?

3.14159 is acurate enough for most applications.

3.14 is rational. However, it is often used as an approximation for pi, which is irrational.