Answer:
15 Units I think..?????
x = 15units
Solving steps:
QS = 16 + 9
QS = 25
Cos(QSR) = RS/QS
Cos(QSR) = x/25
Cos(RST) = ST/RS
[tex] \frac{x}{25} = \frac{9}{x} [/tex]
=> [tex]x {}^{2} = 225[/tex]
=> [tex]x = \sqrt{225} [/tex]
=> x = 15
