Final answer:
The method that is used to select landfill sites within 20 miles of Urbana is 'Within a distance of.' This method allows us to identify landfill sites that fall within a specified distance from a given point, in this case, within 20 miles of Urbana. It helps determine the proximity of landfill sites to urban areas and ensures their accessibility within a specific distance limit.
Step-by-step explanation:
The method that allows us to select landfill sites within 20 miles of Urbana is Within a distance of. This method looks for landfill sites that fall within a specified distance from a given point, in this case, within 20 miles of Urbana.
For example, using this method, we can identify and select landfill sites that are located within a 20-mile radius around Urbana. This helps in determining the proximity of landfill sites to urban areas and ensures their accessibility within a specific distance limit.
By using the "Within a distance of" method, we can find landfill sites that are close to Urbana and within the specified range, making it easier to manage waste disposal activities effectively.