Step-by-step explanation:
the area of a circle (all 360°) is
pi×r²
with r being the radius.
the area of a circle segment is just the corresponding fraction of the whole circle.
so the area of a segment of x degrees is
pi×r² × x/360
in our case we know
pi×42240² × x/360 = 180 mi²
we also know that there are 5280 ft in 1 mile.
so, the radius is actually
42240 / 5280 = 8 miles
and therefore our equation resulting in mi² has to use miles and not ft and has to look that way :
pi×8² × x/360 = 180 mi²
pi×64 × x/360 = 180
pi×64 × x = 180×360
pi×x = 180×360/64 = 1012.5
x = 1012.5/pi = 322.2887598...°
so, the angle of the segment of a circle with the area of 180 mi² and the radius of 8 mi is 322.2887598...°
