Answer:
56.549 feet
Explanation:
Diameter. ft in m
18′0″ 56.55. 678.6 17.24
18′1″ 56.81.
18′2″ 57.07. 684.9
18′3″ 57.33. 688.0
18′4″ 57.60. 691.2
18′5″ 57.86. 694.3 17.64
18′6″ 58.12. 697.4 17.71
18′7″ 58.38 700.6 17.79
18′8″ 58.64 703.7 17.87
18′9″ 58.90. 706.9 17.95
18′10″ 59.17. 710.0 18.03
18′11″ 59.43. 713.1 18.11