Finding the Fourth Proportional to 1,398.98, 1,930.20 and 809.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.98 : 1,930.20 = 809.48 : x
2. Step 2: Convert to fraction form
   1,398.98/1,930.20 = 809.48/x
3. Step 3: Cross multiply
   1,398.98x = 1,930.20 × 809.48
4. Step 4: Simplify right side
   1,398.98x = 1,562,458.30
5. Step 5: Solve for x
   x = 1,562,458.30/1,398.98
6. Step 6: Final answer
   x = 1,116.86