Finding the Fourth Proportional to 1,399.14, 1,931.04 and 809.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.14 : 1,931.04 = 809.55 : x
2. Step 2: Convert to fraction form
   1,399.14/1,931.04 = 809.55/x
3. Step 3: Cross multiply
   1,399.14x = 1,931.04 × 809.55
4. Step 4: Simplify right side
   1,399.14x = 1,563,273.43
5. Step 5: Solve for x
   x = 1,563,273.43/1,399.14
6. Step 6: Final answer
   x = 1,117.31