Answer:
Hence, the percent error is:
4.17%
Explanation:
It is given that:
We measure a piece of rope and find its length to be 12 m.
As we know that the error of measure is 0.5 of the actual length i.e. the length of a rope may vary by 0.5
i.e. the length of a rope may be between 12-0.5 to 12+0.5
i.e. between 11.5 m to 12.5 m.
Hence, the percent error is calculated as:

Hence, the percent error is:
4.17%