1x10-12metres
There are 109 pm in 1 mm.
3 hours
2 hrs
1:45 PM to 3:18 PM is 1 hour and 38 minutes.
There are 16 hours from 9 PM to 1 PM the next day.
1 pm is a billionth of a mm ie 0.000000001 mm.
1 ft = 25400000000 pm = 2.54 x 1010 pm
It is a 3 hour time span or difference as 11 am-12 pm is 1 hour, 12 pm-1 pm is another hour, and 1pm-2 pm is a 3rd.
1000 meters = 1 km
1 inch=0.0254 meters
1 foot is about 0.3 meters.