Finding the Fourth Proportional to 3,942.78, 5,442.30 and 3,143.31

Step by Step Solution

1. Step 1: Write the proportion equation
   3,942.78 : 5,442.30 = 3,143.31 : x
2. Step 2: Convert to fraction form
   3,942.78/5,442.30 = 3,143.31/x
3. Step 3: Cross multiply
   3,942.78x = 5,442.30 × 3,143.31
4. Step 4: Simplify right side
   3,942.78x = 17,106,836.01
5. Step 5: Solve for x
   x = 17,106,836.01/3,942.78
6. Step 6: Final answer
   x = 4,338.78