Answer
98.4%
Work Step by Step
You want to find out the square miles of the land not including Illinois:3,536,278-57,918=3,478,360
You want the percentage of land that is not Illinois so you divide the amount of land you originally have and the amount of land not including Illinois:$\frac{3,478,360}{3,536,278}$=0.9836
Multiply it by 100 to get the percentage and you round to the hundredths:98.4%