Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre, 1 millimetre.

Explanation

To arrange the lengths in increasing magnitude, we will convert all the measurements to the same unit. Let's choose millimeters (mm) as our common unit for comparison.

### Step-by-Step Solution:

1. **Convert 1 metre to millimeters:**
- We know that 1 meter (m) is equal to 1000 millimeters (mm).
- Therefore, \( 1 \text{ m} = 1000 \text{ mm} \).

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