A researcher approximated the number of juniper trees in a region of desert that is roughly square shaped with a side length of 220 kilometers. As part of the process, she counted the number of juniper trees in a small part of the region and determined that the density of the tree was about 86 trees per square kilometer. She assumed the density of juniper trees was the same throughout the region. Which expression would the researcher have most likely used when making her approximation for the number of juniper trees in the square shaped region