Answer:
c.6.9 units (to the nearest tenth of a unit)
Explanation:
sin60=(s/2)/(d/2) where s=side of triangle and d=diameter of circle
sin60=s/d
√(3/4)=s/d
d=s/√(3/4)
d=s√(4/3)
d=2s/√3 and since s=6
d=12/√3
d=√48
d≈6.9282
hope this helps:)sorry if it doesnt