390cm but most running tracks have 8 lanes
From the staggered start, it is 400 meters around. The stagger is calculated by subtracting the extra distance one goes around a wider diameter. For each lane it is double the lane width (which in the Olympics is 1.22m) times pi. for each additional lane.
38cm + 65cm + 47cm = 150cm
0.65m
The circumference of a circle of 65cm radius is about 408.41cm(Circumference = 2*pi*65 cm)
0.65m
65cm
65cm
0.65m
650mm
204.2
8m 65cm
65 centimeters is 0.65 meters.