Two previously undeformed cylindrical specimens of an alloy are to be strain hardened by reducing their cross-sectional areas (while maintaining their circular cross sections). For one specimen, the initial and deformed radii are 17mm and 12mm, respectively. The second specimen, with an initial radius of 13mm, must have the same deformed hardness as the first specimen; compute the second specimen's radius, in mm, after deformation. r=mm