Finding the Fourth Proportional to 1,398.57, 1,930.20 and 809.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.57 : 1,930.20 = 809.09 : x
2. Step 2: Convert to fraction form
   1,398.57/1,930.20 = 809.09/x
3. Step 3: Cross multiply
   1,398.57x = 1,930.20 × 809.09
4. Step 4: Simplify right side
   1,398.57x = 1,561,705.52
5. Step 5: Solve for x
   x = 1,561,705.52/1,398.57
6. Step 6: Final answer
   x = 1,116.64