Finding the Fourth Proportional to 1,399.83, 2,100.17 and 425.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.83 : 2,100.17 = 425.94 : x
2. Step 2: Convert to fraction form
   1,399.83/2,100.17 = 425.94/x
3. Step 3: Cross multiply
   1,399.83x = 2,100.17 × 425.94
4. Step 4: Simplify right side
   1,399.83x = 894,546.41
5. Step 5: Solve for x
   x = 894,546.41/1,399.83
6. Step 6: Final answer
   x = 639.04