To calculate the percent error, you generally need to have both a measured value and a true or accepted value to compare against. The formula for percent error is:
\[ \text{Percent Error} = \left( \frac{|\text{Measured Value} - \text{True Value}|}{\text{True Value}} \right) \times 100% \]
Since you only provided a measurement of 2 feet without a true value, we can't compute a percent error. If you could provide a true or accepted value to compare the measurement against, I can help you find the percent error.