Answer:
±sqrt(7) = r
Step-by-step explanation:
21 = 3r^2
Divide each side by 3
21/3 = 3r^2/3
7 = r^2
Take the square root of each side
±sqrt(7) = sqrt(r^2)
±sqrt(7) = r
A=(απr^2)/360=(απd^2)/1440 (r^2=d^2/4)
α=1440A/(πd^2)
s=απd/360 (where s=arc length) so
s=(1440Aπd)/(360πd^2)
s=4A/d and since A=10mi^2 and d=20mi
s=(4*10)/20
s=2 miles
That would be 18 yards.
Since 3 feet equals 1 yard, you must divide 54 by 3 and you get 18.
