Verified Answer :

If it is the midpoint, then FG= FM+MG


Also, this means that they are of equal lenght, so

FM=MG
5y + 13= 5-3y
5y+3y=5+13
8y=18
y=\(\frac{18}{8}\)=2.25

which means that the two halves are equal to 5y+13=52.25+13=24.25

and FG is double the lenght:

24.25
2=49