Finding the Fourth Proportional to 138,466, 191,083.89 and 81,139.15

Step by Step Solution

1. Step 1: Write the proportion equation
   138,466 : 191,083.89 = 81,139.15 : x
2. Step 2: Convert to fraction form
   138,466/191,083.89 = 81,139.15/x
3. Step 3: Cross multiply
   138,466x = 191,083.89 × 81,139.15
4. Step 4: Simplify right side
   138,466x = 15,504,384,413.29
5. Step 5: Solve for x
   x = 15,504,384,413.29/138,466
6. Step 6: Final answer
   x = 111,972.50