Answer :

To convert the mass of an official MLB baseball from grams (g) to kilograms (kg), you need to follow these steps:

1. Understand the conversion factor:
- 1 kilogram (kg) is equal to 1000 grams (g).

2. Set up the conversion:
- Since you are converting from grams to kilograms, you will divide the mass in grams by 1000.

3. Perform the calculation:
- Take the given mass of the baseball, 145 grams, and convert it to kilograms by dividing by 1000.

[tex]\[ \text{mass in kg} = \frac{\text{mass in g}}{1000} \][/tex]

4. Substitute the given value and calculate:
- Plug in 145 grams into the formula and calculate.

[tex]\[ \text{mass in kg} = \frac{145 \text{ g}}{1000} = 0.145 \text{ kg} \][/tex]

Therefore, the mass of the official MLB baseball in kilograms is 0.145 kg.