Finding the Fourth Proportional to 2,018.78, 3,028.14 and 557.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,018.78 : 3,028.14 = 557.90 : x
2. Step 2: Convert to fraction form
   2,018.78/3,028.14 = 557.90/x
3. Step 3: Cross multiply
   2,018.78x = 3,028.14 × 557.90
4. Step 4: Simplify right side
   2,018.78x = 1,689,399.31
5. Step 5: Solve for x
   x = 1,689,399.31/2,018.78
6. Step 6: Final answer
   x = 836.84