sound like yu hav a big klok with a arm (? minut arm?) that go round
diameter=135 meters
rim leng=pi*diam=3.14159265*135
=424.1150078 meter
speed av tip av hand=angular speed (omega)*radius=0.26 meter/sek
radius=135/2=67.5
omega=0.26/67.5=0.0038518 radians/sekond
1 time around=2pi radians
time=6.2831853/0.0038518
=1631.234 sekonds
round tu 1631 seks or 27.187 minuts