Finding the Fourth Proportional to 139,081.97, 191,957.69 and 81,721.28

Step by Step Solution

1. Step 1: Write the proportion equation
   139,081.97 : 191,957.69 = 81,721.28 : x
2. Step 2: Convert to fraction form
   139,081.97/191,957.69 = 81,721.28/x
3. Step 3: Cross multiply
   139,081.97x = 191,957.69 × 81,721.28
4. Step 4: Simplify right side
   139,081.97x = 15,687,028,132.64
5. Step 5: Solve for x
   x = 15,687,028,132.64/139,081.97
6. Step 6: Final answer
   x = 112,789.80