The square root of 31 is approximately $\sqrt{31} \approx 5.57$.

Would you like more details on how to approximate square roots, or do you have any questions?

Here are some related questions you might find interesting:

1. What is the square root of 32?
2. How do you calculate the square root of a non-perfect square?
3. What is the difference between a perfect square and a non-perfect square?
4. Can square roots be negative?
5. How do you estimate the square root of a number by hand?

Tip: Remember that the square root of a non-perfect square will be an irrational number, meaning it cannot be expressed as a simple fraction.