Finding the Fourth Proportional to 760,139.30, 1,139,940.15 and 261,387.30

Step by Step Solution

1. Step 1: Write the proportion equation
   760,139.30 : 1,139,940.15 = 261,387.30 : x
2. Step 2: Convert to fraction form
   760,139.30/1,139,940.15 = 261,387.30/x
3. Step 3: Cross multiply
   760,139.30x = 1,139,940.15 × 261,387.30
4. Step 4: Simplify right side
   760,139.30x = 297,965,877,970.10
5. Step 5: Solve for x
   x = 297,965,877,970.10/760,139.30
6. Step 6: Final answer
   x = 391,988.52