The maximum number of shrubs (x) = a(area) divided by 15.9
a(area)=37.1*15
37.1*15= 556.5
556.5/15.9=x
556.5/15.9=35
35=x
Add 7.2 each time until you get to 102
This is a matter of plugging in. Specifically 7 for L.
T = 2πsqrt(7/32)
T = (6.28319...)(0.46771...)
T is about 2.93871 seconds