Finding the Fourth Proportional to 1,116.15, 1,540.28 and 618.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.15 : 1,540.28 = 618.81 : x
2. Step 2: Convert to fraction form
   1,116.15/1,540.28 = 618.81/x
3. Step 3: Cross multiply
   1,116.15x = 1,540.28 × 618.81
4. Step 4: Simplify right side
   1,116.15x = 953,137.57
5. Step 5: Solve for x
   x = 953,137.57/1,116.15
6. Step 6: Final answer
   x = 853.95