Answer:
1 km is the greatest measure of length.
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.