There are 640 acres in a square mile. How big( in acres) is a rectangular field that is 0.3 miles by 1.3 miles?

Area= L*W so Area= 1.3miles*.3miles=0.39miles^2 so then 

Area in acres = 0.39miles^2 * 640acres/1sq mile = 249.6 acres

hope this helps! Thank you!