Finding the Fourth Proportional to 1,142.78, 1,713.12 and 557.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.78 : 1,713.12 = 557.45 : x
2. Step 2: Convert to fraction form
   1,142.78/1,713.12 = 557.45/x
3. Step 3: Cross multiply
   1,142.78x = 1,713.12 × 557.45
4. Step 4: Simplify right side
   1,142.78x = 954,978.74
5. Step 5: Solve for x
   x = 954,978.74/1,142.78
6. Step 6: Final answer
   x = 835.66