Step 1: Start with the fraction 21/50.

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

21 ÷ 50 = 0.42

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

0.42 × 100 = 42.0%

Final Answer: 21/50 as a percentage is 42.0%.