This is what the website says...
Size   Head Angle   Seat Angle   Top Tube   Head Tube   Chain Stay   Wheel Base   Standover Height
S/46,5   72.0   74.0   53.0   14.5   42.0   99.0     75.4
M/50,0   72.5   73.5   54.5   16.5   42.0   99.5     77.7
M/L53,5   72.5   73.0   56.0   18.5   42.0   100.7  79.0
L/55,5   72.5   73.0   57.5   20.5   42.0   102.2  81.3
XL/58,5   72.5   72.5   59.5   22.5   42.0   103.7  83.3
If you click on my link you see it with better formatting.
I think Giant do it a bit different in terms of how they size bikes.
I'm 5'10" and it was right for me.
It is a M and not an M/L.
Thanks