diameter=side
find area of field (square) and area of sprinkler (circle)
ara of square=side^2
area of circle=pir^2
area of square=12^2=144
area of circle=pir^2
d/2=r
12/2=6=r
area=pi6^2
area=36pi
aprox pi=3.14
area=113.04
area wasted=area of field-arrea of sprinlker
area wasted=144-113.04=30.96 m^2