Finding the Fourth Proportional to 1,398.72, 1,929.72 and 809.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.72 : 1,929.72 = 809.04 : x
2. Step 2: Convert to fraction form
   1,398.72/1,929.72 = 809.04/x
3. Step 3: Cross multiply
   1,398.72x = 1,929.72 × 809.04
4. Step 4: Simplify right side
   1,398.72x = 1,561,220.67
5. Step 5: Solve for x
   x = 1,561,220.67/1,398.72
6. Step 6: Final answer
   x = 1,116.18