Bit of a tricky Q, that. A gauged arch is one consisting of wedged stones, whose joints project to a single point. At first glance, it might seem to be that only a simple, sem…i-circular or Roman arch could be the only possibility. However, if the wedging was variable and reducing toward the keystone, it is possible to create a pointed or gothic gauged arch..
(if your teacher squabbles, I could sketch out and email a more detailed explanation) ( Full Answer )