Finding the Fourth Proportional to 408,549.05, 612,921.98 and 128,066.30

Step by Step Solution

1. Step 1: Write the proportion equation
   408,549.05 : 612,921.98 = 128,066.30 : x
2. Step 2: Convert to fraction form
   408,549.05/612,921.98 = 128,066.30/x
3. Step 3: Cross multiply
   408,549.05x = 612,921.98 × 128,066.30
4. Step 4: Simplify right side
   408,549.05x = 78,494,647,422.83
5. Step 5: Solve for x
   x = 78,494,647,422.83/408,549.05
6. Step 6: Final answer
   x = 192,130.29