* Convert all measurements to the same unit: Let's convert everything to millimeters (mm) for easy comparison.

* 6 kilometers (km): 1 km = 1,000,000 mm, so 6 km = 6,000,000 mm

* 60 meters (m): 1 m = 1000 mm, so 60 m = 60,000 mm

* 600 centimeters (cm): 1 cm = 10 mm, so 600 cm = 6,000 mm

* 6000 millimeters (mm): Already in millimeters.

* Compare the values:

* 6,000,000 mm

* 60,000 mm

* 6,000 mm

* 6,000 mm

* The greatest measurement is 6 kilometers (6,000,000 millimeters).