Finding the Fourth Proportional to 1,399.30, 1,930.90 and 809.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.30 : 1,930.90 = 809.83 : x
2. Step 2: Convert to fraction form
   1,399.30/1,930.90 = 809.83/x
3. Step 3: Cross multiply
   1,399.30x = 1,930.90 × 809.83
4. Step 4: Simplify right side
   1,399.30x = 1,563,700.75
5. Step 5: Solve for x
   x = 1,563,700.75/1,399.30
6. Step 6: Final answer
   x = 1,117.49