Answer :

To determine how many decimeters (dm) are in 1.25 meters (m), we need to understand the relationship between meters and decimeters. One meter is equivalent to 10 decimeters.

Given:
[tex]\[ 1 \, \text{meter} = 10 \, \text{decimeters} \][/tex]

We are asked to convert 1.25 meters into decimeters. Here are the steps to do this conversion:

1. Identify the Conversion Factor:
The conversion factor from meters to decimeters is 10. This means that for every 1 meter, there are 10 decimeters.

2. Multiply the Number of Meters by the Conversion Factor:
We need to multiply the given number of meters (1.25) by the conversion factor (10) to find the equivalent number of decimeters.
[tex]\[ 1.25 \, \text{meters} \times 10 \, \frac{\text{decimeters}}{\text{meter}} = 12.5 \, \text{decimeters} \][/tex]

3. Conclusion:
Therefore, 1.25 meters is equal to 12.5 decimeters.

Hence, the correct answer is:
[tex]\[ \boxed{12.5 \, \text{decimeters}} \][/tex]

From the given options, the correct choice is:

A. 12.5 dm