There are 31+42+50+61=184 total females, and 50+61=111 females in grades 11 and 12, so the percentage is 111/184*100=60.33 percent, which can be rounded to 60%.
Formula for the area of a quarter circle: A = (pi x r^2) / 4
A = (pi x 2^2) / 4
A = (pi x 4) / 4
A = 4pi / 4
A = 1pi = 3.14 square miles
Hope this helps! :)