Step 1: Start with the fraction 17/21.

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

17 ÷ 21 = 0.8095

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

0.8095 × 100 = 80.95%

Final Answer: 17/21 as a percentage is 80.95%.