Finding the Fourth Proportional to 1,399.17, 1,929.17 and 1,223.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.17 : 1,929.17 = 1,223.87 : x
2. Step 2: Convert to fraction form
   1,399.17/1,929.17 = 1,223.87/x
3. Step 3: Cross multiply
   1,399.17x = 1,929.17 × 1,223.87
4. Step 4: Simplify right side
   1,399.17x = 2,361,048.92
5. Step 5: Solve for x
   x = 2,361,048.92/1,399.17
6. Step 6: Final answer
   x = 1,687.47