Finding the Fourth Proportional to 256,856.15, 354,461.82 and 142,139.60

Step by Step Solution

1. Step 1: Write the proportion equation
   256,856.15 : 354,461.82 = 142,139.60 : x
2. Step 2: Convert to fraction form
   256,856.15/354,461.82 = 142,139.60/x
3. Step 3: Cross multiply
   256,856.15x = 354,461.82 × 142,139.60
4. Step 4: Simplify right side
   256,856.15x = 50,383,059,537.76
5. Step 5: Solve for x
   x = 50,383,059,537.76/256,856.15
6. Step 6: Final answer
   x = 196,152.83