A firefighter mounts the nozzle of his fire hose a distance 30.5 m away from the edge of a burning building so that it sprays from ground level at a 45° angle above the horizontal. After quenching a hotspot at a height of 9.45 m, the firefighter adjusts the nozzle diameter so that the water hits the building at a height of 18.7 m. By what factor was the nozzle diameter changed? Assume that the diameter of the hose stays the same, and treat the water as an ideal fluid.