Finding the Fourth Proportional to 1,123.78, 1,550.80 and 626.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.78 : 1,550.80 = 626.39 : x
2. Step 2: Convert to fraction form
   1,123.78/1,550.80 = 626.39/x
3. Step 3: Cross multiply
   1,123.78x = 1,550.80 × 626.39
4. Step 4: Simplify right side
   1,123.78x = 971,400.93
5. Step 5: Solve for x
   x = 971,400.93/1,123.78
6. Step 6: Final answer
   x = 864.41