At a school carnival, the diameter of the mat of a trampoline is 16 feet and the diameter of its metal frame is 18 feet. What is the length, in feet, of the metal frame that surrounds the trampoline? Use 3.14 for π and round your answer to the nearest tenth.
A) 50.2 feet
B) 56.5 feet
C) 100.5 feet
D) 113.0 feet