Finding the Fourth Proportional to 1,013.50, 1,398.73 and 620.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.50 : 1,398.73 = 620.45 : x
2. Step 2: Convert to fraction form
   1,013.50/1,398.73 = 620.45/x
3. Step 3: Cross multiply
   1,013.50x = 1,398.73 × 620.45
4. Step 4: Simplify right side
   1,013.50x = 867,842.03
5. Step 5: Solve for x
   x = 867,842.03/1,013.50
6. Step 6: Final answer
   x = 856.28