Okay.
A pet owner reports false alarms from a dual-tech motion sensor. The room is 18 ft × 24 ft. The sensor is rated for 40 ft at 100% sensitivity, but you must reduce sensitivity to 65% to ignore a 35 lb dog. The sensor is mounted 8 ft high on the long wall.
Calculate the effective detection range at 65% sensitivity (assuming linear reduction). Then use the Pythagorean theorem to check if the far corner of the room is still covered.