So we know that at 55 degrees it’s 690 mL, so first we do 690/55≈12,5454...
Now we know that for 1 degree its ≈12.5454.. mL and we want for 30 degrees so we do 12.5454.. x 30≈ 376.363636... mL.
The volume the gas will occupy at 30 degrees is 376.363636... mL.