Finding the Fourth Proportional to 1,142.78, 1,577.04 and 618.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.78 : 1,577.04 = 618.82 : x
2. Step 2: Convert to fraction form
   1,142.78/1,577.04 = 618.82/x
3. Step 3: Cross multiply
   1,142.78x = 1,577.04 × 618.82
4. Step 4: Simplify right side
   1,142.78x = 975,903.89
5. Step 5: Solve for x
   x = 975,903.89/1,142.78
6. Step 6: Final answer
   x = 853.97