【正确答案】已知d=40mm、P=7mm
d_D=0.518P=0.518×7mm=3.626mm
M=d_z+4.864d_D-1.866P
=d-0.5P+4.864d_D-1.866P
=40mm-0.5×7mm+4.864×3.626mm-1.866×7mm
=41.075mm
[答] 量针直径d_D为3.626mm，量针测量距M为41.075mm。