To find Eric's relative error, we can use the formula for relative error:
\[ \text{Relative Error} = \frac{|\text{Measured Value} - \text{Actual Value}|}{|\text{Actual Value}|} \]
In this case, the measured value is 7.54 cm and the actual value is 8 cm.
First, we calculate the absolute error:
\[ \text{Absolute Error} = |\text{Measured Value} - \text{Actual Value}| = |7.54 - 8| = | -0.46| = 0.46 \]
Next, we plug the values into the relative error formula:
\[ \text{Relative Error} = \frac{0.46}{8} \]
Calculating this gives:
\[ \text{Relative Error} = 0.0575 \]
To express the relative error to the nearest thousandth, we round 0.0575:
\[ \text{Relative Error (rounded)} = 0.058 \]
Thus, Eric's relative error to the nearest thousandth is 0.058.