A $5$th percentile U$.$S$.$ male has forward reach of $843$ mm$.$ His shoulder is $450$ mm above a horizontal work surface. Calculate the radius of the ZCR on the desktop.

ZCR is defined as the zone of convenient reach

The reach zone is such that the worker can reach work objects, either from standing or from a sitting position, without having to lean forward. The ability to do this depends on two variables,

and the forward reach distance and rhe vertical distance between the shoulder and the work