Step 1: Start with the fraction 3/12.

Step 2: To convert a fraction into a percentage, divide the numerator by the denominator.

3 ÷ 12 = 0.25

Step 3: Multiply the result by 100 to get the percentage.

0.25 × 100 = 25.0%

Final Answer: 3/12 as a percentage is 25.0%.