Finding the Fourth Proportional to 1,013.43, 1,398.56 and 620.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.43 : 1,398.56 = 620.31 : x
2. Step 2: Convert to fraction form
   1,013.43/1,398.56 = 620.31/x
3. Step 3: Cross multiply
   1,013.43x = 1,398.56 × 620.31
4. Step 4: Simplify right side
   1,013.43x = 867,540.75
5. Step 5: Solve for x
   x = 867,540.75/1,013.43
6. Step 6: Final answer
   x = 856.04