Answer:
B) 63 ft.
Explanation:
To find how long it takes for a rotation, we need to find the circumference.
To do so, we use the formula 2(pi)r
To find the radius, we divide the diameter in half :
d = 20
r = d/2
r = 20 / 2
r = 10
Then, we plug that into the formula :
2(pi)10
Insert that into your calculator :
2(pi)10 = 62.83
Simplify :
62.83 = 63 ft.