Finding the Fourth Proportional to 129,142.91, 178,216.04 and 71,780.76

Step by Step Solution

1. Step 1: Write the proportion equation
   129,142.91 : 178,216.04 = 71,780.76 : x
2. Step 2: Convert to fraction form
   129,142.91/178,216.04 = 71,780.76/x
3. Step 3: Cross multiply
   129,142.91x = 178,216.04 × 71,780.76
4. Step 4: Simplify right side
   129,142.91x = 12,792,482,795.39
5. Step 5: Solve for x
   x = 12,792,482,795.39/129,142.91
6. Step 6: Final answer
   x = 99,056.80