| 摘要 |
A device for determining the range/height of distant objects using the triangulation method. The device includes a palm-sized housing having merely four main components; (1) a retractable tape measure; (2) a sighting slot; (3) a pendulum and (4) a calibrated graph. A reel is disposed on the rear wall of the housing to provide means for retracting the tape measure. The calibrated graph is imprinted on the face of a thin sheet, which sheet is attached to the front wall of the housing. A transparent cover is disposed to protect the face of the sheet. An offset portion on the sheet functions to prevent the pendulum from swinging freely when the device is not in use. The sighting slot is positioned at the top of the housing.
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