Finding the Fourth Proportional to 538,156.71, 806,839.79 and 257,870.79

Step by Step Solution

1. Step 1: Write the proportion equation
   538,156.71 : 806,839.79 = 257,870.79 : x
2. Step 2: Convert to fraction form
   538,156.71/806,839.79 = 257,870.79/x
3. Step 3: Cross multiply
   538,156.71x = 806,839.79 × 257,870.79
4. Step 4: Simplify right side
   538,156.71x = 208,060,412,761.38
5. Step 5: Solve for x
   x = 208,060,412,761.38/538,156.71
6. Step 6: Final answer
   x = 386,616.78