Point by point illuminance: PE Power General Applications practice question

A warehouse aisle is lit by high-bay LED luminaires. One luminaire hangs 10 ft above the horizontal work plane. Point P on the work plane lies 7.5 ft horizontally from the spot directly below the luminaire. The luminaire's photometric data give an intensity of 3,000 cd in the direction of point P.

Treating the luminaire as a point source and counting only its direct light, the horizontal illuminance at P is most nearly: