'Screen Ratio' in cameras

[V2lsbGJsM3BpYw== 410]

So, I'm making a laptop rig, and the screen is a 16:10 ratio. It also is reflective (using a camera. The reflection works fine, but in the camera keyframing, I saw a thing saying 'Screen ratio'. Now the reflection is fine as it is, but I was wondering whether this could make it any better. 'The ratio between the width and height of the projection' could be 16, 10 or 6! Which do I type in?

[david 8.4k]

16/10=1.6

 

1.6

[V2lsbGJsM3BpYw== 410]

16/10=1.6

 

1.6

Ah thank you!