Finding the Fourth Proportional to 1,012.27, 1,396.32 and 618.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.27 : 1,396.32 = 618.61 : x
2. Step 2: Convert to fraction form
   1,012.27/1,396.32 = 618.61/x
3. Step 3: Cross multiply
   1,012.27x = 1,396.32 × 618.61
4. Step 4: Simplify right side
   1,012.27x = 863,777.52
5. Step 5: Solve for x
   x = 863,777.52/1,012.27
6. Step 6: Final answer
   x = 853.31