Final answer:
The tachometer is a gauge that measures the rotation speed of the engine in revolutions per minute (RPM).
Step-by-step explanation:
The tachometer is not the gauge that indicates the number of miles the vehicle has been driven since it was manufactured. The tachometer is a gauge that measures the rotation speed of the engine in revolutions per minute (RPM). It is used to monitor the engine's performance and help drivers determine when to shift gears in a manual transmission vehicle.