Finding the Fourth Proportional to 1,223.78, 1,687.46 and 1,105.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.78 : 1,687.46 = 1,105.74 : x
2. Step 2: Convert to fraction form
   1,223.78/1,687.46 = 1,105.74/x
3. Step 3: Cross multiply
   1,223.78x = 1,687.46 × 1,105.74
4. Step 4: Simplify right side
   1,223.78x = 1,865,892.02
5. Step 5: Solve for x
   x = 1,865,892.02/1,223.78
6. Step 6: Final answer
   x = 1,524.70