Suppose you did an experiment to measure the boiling point of water and your results average to 1015C. An error of 25 from an estimate of 50 25 is 50. So you plug in 48 for guess number and 50 for result number.
Relative Error Absolute Error Known Value.
We dont know the actual measurement so the best we can do is use the measured value. Convert that to a percentage by multiplying by 100 and adding a sign. So you have 48 inches minus 50 inches is. So 40 would be 40 divided by 100 or40.