the total length of the segment is 37, and half of the segment is 18, so to find the other half of the segment, you would subtract the half from the total amount: 37-18=19
if the entire segment, XZ = 37, and you have part of that segment, YZ as 18, then all you need to do is subtract 18 from 37, and you will get the other part of the segment, 19
