Answer:
Suppose the next case.
You want to buy an object from another state or country, you know that the cost of this object is C, and for bringing it from another place, you need to pay a tax, such that you do not know the exact value of the tax, you know that this can be between 3% and 9%.
Then the tax can be written as:
6% ± 3%
then the error is 3%, this means that the percent error is:
(3%/6%)*100% = 50%
Then you know that there is an error of 50% in the tax.
This can be helpful so you can estimate the maximum and minimum cost of tax that you will pay for this purchase.
Also there are a lot of situations where the percent error give us a lot of information.
"a measure of 10 cm with an error of 1 cm"
The percent error is: (1cm/10cm)*100% = 10%
And in a measure of 3cm with an error of 1cm we have:
(1cm/3cm) = 33.33%
In both cases we have the came error, but different percent error.
Then the percent error also tell us how much the error affects our measure.
