Finding the Fourth Proportional to 1,399.92, 2,099.89 and 426.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.92 : 2,099.89 = 426.02 : x
2. Step 2: Convert to fraction form
   1,399.92/2,099.89 = 426.02/x
3. Step 3: Cross multiply
   1,399.92x = 2,099.89 × 426.02
4. Step 4: Simplify right side
   1,399.92x = 894,582.51
5. Step 5: Solve for x
   x = 894,582.51/1,399.92
6. Step 6: Final answer
   x = 639.02