sally9306 said:
well, i read that, but i cant get it Can you form any questions for us about it?
is relative error = measured area/actual area ? Nope.
That reference says, "[Relative error is] defined as the absolute error divided by the true value."
That reference also says, "To compute the absolute error, the difference between measurement and the true value is taken."
In your exercise, the measurement is 174.2 and the true value is 149.6, so their difference is the absolute error.
\(\displaystyle \text{Relative Error} \;=\; \frac{\text{Absolute Error}}{\text{True Value}}\)