Finding the Fourth Proportional to 678,078.78, 935,680.55 and 406,139.69

Step by Step Solution

1. Step 1: Write the proportion equation
   678,078.78 : 935,680.55 = 406,139.69 : x
2. Step 2: Convert to fraction form
   678,078.78/935,680.55 = 406,139.69/x
3. Step 3: Cross multiply
   678,078.78x = 935,680.55 × 406,139.69
4. Step 4: Simplify right side
   678,078.78x = 380,017,001,806.93
5. Step 5: Solve for x
   x = 380,017,001,806.93/678,078.78
6. Step 6: Final answer
   x = 560,431.93