Finding the Fourth Proportional to 1,399.48, 1,931.04 and 809.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.48 : 1,931.04 = 809.98 : x
2. Step 2: Convert to fraction form
   1,399.48/1,931.04 = 809.98/x
3. Step 3: Cross multiply
   1,399.48x = 1,931.04 × 809.98
4. Step 4: Simplify right side
   1,399.48x = 1,564,103.78
5. Step 5: Solve for x
   x = 1,564,103.78/1,399.48
6. Step 6: Final answer
   x = 1,117.63