**Answer:**

1 : 3000

**Step-by-step explanation:**

Given that:

Scale measurement as following:

4 centimeters are equal to 120 meters.

**To find:**

The scale factor = ?

**Solution:**

First of all, let us learn about the definition of scale factor.

**Scale factor** means 1 unit on scale is equal to what length of actual measurement.

We are given that 4 cm on scale is equal to 120 meters of actual length.

We need to find nothing but how much 1 cm of scale is equal to actual length.

4 cm of scale = 120 meters or 12000 cm of actual length

Dividing by 4 on both sides, we get:

= 1 cm of scale = = 3000 cm of actual length

Therefore, the scale factor is <em>**1 : 3000**</em>