Answer:
6.93 cm
Step-by-step explanation:
You have a right triangle (90°), so you do as follow:
If I understand correctly, you are looking for the hypotenuse so
[tex]cos(30) = \frac{PQ}{QR} = \frac{8 cm}{QR}[/tex]
That is equal to [tex]QR = cos(30)*8 cm = 6.928 cm[/tex]