Answer:
r=8.74
Explanation:
so firstly you need the formula volume equals to 1/3 S x h
you than multiply v9lume by 3
so 1920 equals to S x h
you devide 1920 by h so you get S=240
because S=πr2 you devide 240 by π
you get 76.433
that us r2 so you use square root and get 8.74 feet