name 'sqrt' is not defined

This error occurs when you try to use the square root function without importing it from the math module.

To fix this, you need to import the sqrt function from the math module. Here's an example:

import math

x = math.sqrt(25)

print(x)

Output:

5.0

In this example, we imported the math module and used the sqrt function to calculate the square root of 25. The result is then printed to the console.