Chapter 4 - Section 4.7 - Relative Error and Percent of Error - Exercise - Page 191: 4

100 V, 50 V, 0.004, 0.4%

For the measurement 12,500 V, we have The precision is 100 V The greatest possible error is one-half the precision: $0.5\cdot 100 \ V=50 \ V$ The relative error is $relative~error=\dfrac{greatest~possible~error}{measurement}$ $\frac{50\ V}{12,500\ V}=0.004$ The percent of error is $0.4\%$.