We need to find the percentage of the extra feet that she measured, so first we have to find out how much that is. We can do this by simply subtracting:
4.27 - 4 = 0.27
Now we can set up a proportion to find the percentage.

Solve for x
0.27 x 100 = 27
27/4 = 6.75
The answer is
6.75% :)
Hopefully this helps! If you have any more questions or don't understand, feel free to DM me, and I'll get back to you ASAP! :)