Use the image to find the measure

The measure of the segment GH is 5.3

Here is the simplest way I can explain it: Since you know the entire line(FH) is 15 mm and you know that the first part of the line(FG) is 9.7 mm, to find the length of the rest of the line(GH) all you have to do is subtract 15 by 9.7

Here is the work
15-9.7=5.3

I hope this helped!

Answer is a not really sure tho