Finding the Fourth Proportional to 142,639.89, 196,845.47 and 78,108.09

Step by Step Solution

1. Step 1: Write the proportion equation
   142,639.89 : 196,845.47 = 78,108.09 : x
2. Step 2: Convert to fraction form
   142,639.89/196,845.47 = 78,108.09/x
3. Step 3: Cross multiply
   142,639.89x = 196,845.47 × 78,108.09
4. Step 4: Simplify right side
   142,639.89x = 15,375,223,296.31
5. Step 5: Solve for x
   x = 15,375,223,296.31/142,639.89
6. Step 6: Final answer
   x = 107,790.49