Finding the Fourth Proportional to 256,878.50, 354,258.17 and 220,568.55

Step by Step Solution

1. Step 1: Write the proportion equation
   256,878.50 : 354,258.17 = 220,568.55 : x
2. Step 2: Convert to fraction form
   256,878.50/354,258.17 = 220,568.55/x
3. Step 3: Cross multiply
   256,878.50x = 354,258.17 × 220,568.55
4. Step 4: Simplify right side
   256,878.50x = 78,138,210,882.55
5. Step 5: Solve for x
   x = 78,138,210,882.55/256,878.50
6. Step 6: Final answer
   x = 304,183.54