Answer
about 5%
Work Step by Step
The formula for area is l*w=A
The given measurement is to the nearest 0.5 meters. That means that the greatest possible error is 0.25 meters
$A=(18.5)(7.5)$
$A=138.75$
$A=(18.5)(7.25)$
$A=132.3125$
$A=(18.75)(7.75)$
$A=145.3125$
$|132.3125-138.75|$ absolute value to find the difference in the area between the minimum area and the measured area
$6.4375$
$|145.3125-138.75|$absolute value to find the difference in the area between the maximum area and the measured area
$6.5625$
$\frac{6.5625}{138.75}\approx0.05$, or 5%
greatest possible percent error=greatest diference in area/measured area
