Why the Royal Navy chose 9.2-inch guns

Why was a 9.2-inch gun used instead of an eight- or eleven-inch gun?

Eight inches was considered too weak, while eleven inches was too slow and difficult to maintain; 9.2 inches was the preferred middle ground.

The 9.2-inch gun was the compromise selected for a first-rate armored cruiser. Eight inches was judged to lack stopping power, while an eleven-inch weapon was too slow-firing and difficult to maintain effectively at long range. The chosen calibre balanced destructive effect with rate of fire and practical upkeep. It occupied the middle ground that the designers wanted for the Orlando class.