Finding the Fourth Proportional to 1,086.18, 1,628.83 and 392.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.18 : 1,628.83 = 392.86 : x
2. Step 2: Convert to fraction form
   1,086.18/1,628.83 = 392.86/x
3. Step 3: Cross multiply
   1,086.18x = 1,628.83 × 392.86
4. Step 4: Simplify right side
   1,086.18x = 639,902.15
5. Step 5: Solve for x
   x = 639,902.15/1,086.18
6. Step 6: Final answer
   x = 589.13