Complex sentence: Fra Zorzi based the sizing of the various elements on the number three, because of its association with the Trinity: the nave should be nine paces wide and 27 paces long, each side chapel three paces wide.
Split into simpler sentences: Fra Zorzi based the sizing of the various elements on the number three, because of its association with the trinity. The Nave should be nine paces wide and 27 paces long, each side chapel three paces wide.