Finding the Fourth Proportional to 139,815.92, 209,557.38 and 80,528.78

Step by Step Solution

1. Step 1: Write the proportion equation
   139,815.92 : 209,557.38 = 80,528.78 : x
2. Step 2: Convert to fraction form
   139,815.92/209,557.38 = 80,528.78/x
3. Step 3: Cross multiply
   139,815.92x = 209,557.38 × 80,528.78
4. Step 4: Simplify right side
   139,815.92x = 16,875,400,151.40
5. Step 5: Solve for x
   x = 16,875,400,151.40/139,815.92
6. Step 6: Final answer
   x = 120,697.27