Finding the Fourth Proportional to 1,116.27, 1,540.32 and 618.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.27 : 1,540.32 = 618.80 : x
2. Step 2: Convert to fraction form
   1,116.27/1,540.32 = 618.80/x
3. Step 3: Cross multiply
   1,116.27x = 1,540.32 × 618.80
4. Step 4: Simplify right side
   1,116.27x = 953,142.31
5. Step 5: Solve for x
   x = 953,142.31/1,116.27
6. Step 6: Final answer
   x = 853.86