Finding the Fourth Proportional to 129,056.37, 178,078.55 and 72,456.81

Step by Step Solution

1. Step 1: Write the proportion equation
   129,056.37 : 178,078.55 = 72,456.81 : x
2. Step 2: Convert to fraction form
   129,056.37/178,078.55 = 72,456.81/x
3. Step 3: Cross multiply
   129,056.37x = 178,078.55 × 72,456.81
4. Step 4: Simplify right side
   129,056.37x = 12,903,003,300.14
5. Step 5: Solve for x
   x = 12,903,003,300.14/129,056.37
6. Step 6: Final answer
   x = 99,979.59