Finding the Fourth Proportional to 139,878.54, 209,651.13 and 80,591.34

Step by Step Solution

1. Step 1: Write the proportion equation
   139,878.54 : 209,651.13 = 80,591.34 : x
2. Step 2: Convert to fraction form
   139,878.54/209,651.13 = 80,591.34/x
3. Step 3: Cross multiply
   139,878.54x = 209,651.13 × 80,591.34
4. Step 4: Simplify right side
   139,878.54x = 16,896,065,499.21
5. Step 5: Solve for x
   x = 16,896,065,499.21/139,878.54
6. Step 6: Final answer
   x = 120,790.98