Finding the Fourth Proportional to 1,398.45, 1,929.86 and 809.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.45 : 1,929.86 = 809.08 : x
2. Step 2: Convert to fraction form
   1,398.45/1,929.86 = 809.08/x
3. Step 3: Cross multiply
   1,398.45x = 1,929.86 × 809.08
4. Step 4: Simplify right side
   1,398.45x = 1,561,411.13
5. Step 5: Solve for x
   x = 1,561,411.13/1,398.45
6. Step 6: Final answer
   x = 1,116.53