Finding the Fourth Proportional to 5,781.27, 7,978.20 and 3,128.73

Step by Step Solution

1. Step 1: Write the proportion equation
   5,781.27 : 7,978.20 = 3,128.73 : x
2. Step 2: Convert to fraction form
   5,781.27/7,978.20 = 3,128.73/x
3. Step 3: Cross multiply
   5,781.27x = 7,978.20 × 3,128.73
4. Step 4: Simplify right side
   5,781.27x = 24,961,592.04
5. Step 5: Solve for x
   x = 24,961,592.04/5,781.27
6. Step 6: Final answer
   x = 4,317.66