Step 1: Start with the fraction 40/80.

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

40 ÷ 80 = 0.5

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

0.5 × 100 = 50.0%

Final Answer: 40/80 as a percentage is 50.0%.