Finding the Fourth Proportional to 1,398.87, 1,929.96 and 839.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.87 : 1,929.96 = 839.52 : x
2. Step 2: Convert to fraction form
   1,398.87/1,929.96 = 839.52/x
3. Step 3: Cross multiply
   1,398.87x = 1,929.96 × 839.52
4. Step 4: Simplify right side
   1,398.87x = 1,620,240.02
5. Step 5: Solve for x
   x = 1,620,240.02/1,398.87
6. Step 6: Final answer
   x = 1,158.25