Finding the Fourth Proportional to 1,142.59, 1,576.78 and 618.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.59 : 1,576.78 = 618.63 : x
2. Step 2: Convert to fraction form
   1,142.59/1,576.78 = 618.63/x
3. Step 3: Cross multiply
   1,142.59x = 1,576.78 × 618.63
4. Step 4: Simplify right side
   1,142.59x = 975,443.41
5. Step 5: Solve for x
   x = 975,443.41/1,142.59
6. Step 6: Final answer
   x = 853.71