Given:
R is the midpoint of QS.
[tex]RS=5\text{,RT}=13[/tex]
The midpoint is the point on a line segment equally distant from the two endpoints.
It gives,
[tex]\begin{gathered} QR=RS\ldots\ldots\text{. R is midpoint of QS} \\ \Rightarrow QR=5 \end{gathered}[/tex]
Also,
[tex]\begin{gathered} RS+ST=RT \\ 5+ST=13 \\ ST=13-5 \\ ST=8 \end{gathered}[/tex]
So, QT is calculated as,
[tex]\begin{gathered} QT=QR+RE+ST \\ QT=5+5+8=18 \end{gathered}[/tex]
Answer: QT = 18
