Finding the Fourth Proportional to 1,398.52, 1,929.88 and 839.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.52 : 1,929.88 = 839.24 : x
2. Step 2: Convert to fraction form
   1,398.52/1,929.88 = 839.24/x
3. Step 3: Cross multiply
   1,398.52x = 1,929.88 × 839.24
4. Step 4: Simplify right side
   1,398.52x = 1,619,632.49
5. Step 5: Solve for x
   x = 1,619,632.49/1,398.52
6. Step 6: Final answer
   x = 1,158.10