Finding the Fourth Proportional to 1,011.57, 1,395.98 and 618.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,011.57 : 1,395.98 = 618.81 : x
2. Step 2: Convert to fraction form
   1,011.57/1,395.98 = 618.81/x
3. Step 3: Cross multiply
   1,011.57x = 1,395.98 × 618.81
4. Step 4: Simplify right side
   1,011.57x = 863,846.38
5. Step 5: Solve for x
   x = 863,846.38/1,011.57
6. Step 6: Final answer
   x = 853.97