Finding the Fourth Proportional to 85.71, 128.76 and 83.82

Step by Step Solution

1. Step 1: Write the proportion equation
   85.71 : 128.76 = 83.82 : x
2. Step 2: Convert to fraction form
   85.71/128.76 = 83.82/x
3. Step 3: Cross multiply
   85.71x = 128.76 × 83.82
4. Step 4: Simplify right side
   85.71x = 10,792.66
5. Step 5: Solve for x
   x = 10,792.66/85.71
6. Step 6: Final answer
   x = 125.92