Finding the Fourth Proportional to 1,142.58, 1,576.77 and 618.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.58 : 1,576.77 = 618.61 : x
2. Step 2: Convert to fraction form
   1,142.58/1,576.77 = 618.61/x
3. Step 3: Cross multiply
   1,142.58x = 1,576.77 × 618.61
4. Step 4: Simplify right side
   1,142.58x = 975,405.69
5. Step 5: Solve for x
   x = 975,405.69/1,142.58
6. Step 6: Final answer
   x = 853.69