Finding the Fourth Proportional to 3,989.73, 5,978.54 and 1,906.88

Step by Step Solution

1. Step 1: Write the proportion equation
   3,989.73 : 5,978.54 = 1,906.88 : x
2. Step 2: Convert to fraction form
   3,989.73/5,978.54 = 1,906.88/x
3. Step 3: Cross multiply
   3,989.73x = 5,978.54 × 1,906.88
4. Step 4: Simplify right side
   3,989.73x = 11,400,318.93
5. Step 5: Solve for x
   x = 11,400,318.93/3,989.73
6. Step 6: Final answer
   x = 2,857.42