Respuesta :
You may use the law of sines, that states that in every triangle the ratio between a side and the sine of the opposite angle is constant.
So, in your case, we have
[tex]\dfrac{QR}{\sin(\hat{S})}=\dfrac{RS}{\sin(\hat{Q})}[/tex]
We know that [tex]\hat{S}[/tex] is 90 degrees, so its sine is 1. Also, we know that RS=26. So, the equation becomes
[tex]QR=\dfrac{26}{\sin(54)}[/tex]
