Greatest measure of length. 30,000 millimeters 500 meters 1 kilometer or 6000 centimeters

1 km is the greatest measure of length.

Step-by-step explanation:

To solve this question, first we will convert all measures into same unit then by comparing them we can tell the greatest length.

1 km = 1000 m = ( 1000 × 1000 ) mm = 1,000,000 mm

500 meter = ( 500 × 1000 mm ) = 500,000 mm

6000 cm = ( 6000 × 10 mm ) = 60,000 mm

30000 mm = 30,000 mm

Now we will arrange these lengths from lowest to longest.

30,000 mm < 60,000 mm < 500,000 mm < 1,000,000 mm

So out of these five lengths 1,000,000 mm is the longest.

Therefore, 1 km is the greatest measure of length.

c-4 is the final answer! : )