Finding the Fourth Proportional to 426,978.72, 640,446.21 and 127,461.78

Step by Step Solution

1. Step 1: Write the proportion equation
   426,978.72 : 640,446.21 = 127,461.78 : x
2. Step 2: Convert to fraction form
   426,978.72/640,446.21 = 127,461.78/x
3. Step 3: Cross multiply
   426,978.72x = 640,446.21 × 127,461.78
4. Step 4: Simplify right side
   426,978.72x = 81,632,413,920.85
5. Step 5: Solve for x
   x = 81,632,413,920.85/426,978.72
6. Step 6: Final answer
   x = 191,186.14