Finding the Fourth Proportional to 85.59, 128.57 and 82.71

Step by Step Solution

1. Step 1: Write the proportion equation
   85.59 : 128.57 = 82.71 : x
2. Step 2: Convert to fraction form
   85.59/128.57 = 82.71/x
3. Step 3: Cross multiply
   85.59x = 128.57 × 82.71
4. Step 4: Simplify right side
   85.59x = 10,633.61
5. Step 5: Solve for x
   x = 10,633.61/85.59
6. Step 6: Final answer
   x = 124.24