Finding the Fourth Proportional to 142,306.39, 196,375.15 and 78,640.39

Step by Step Solution

1. Step 1: Write the proportion equation
   142,306.39 : 196,375.15 = 78,640.39 : x
2. Step 2: Convert to fraction form
   142,306.39/196,375.15 = 78,640.39/x
3. Step 3: Cross multiply
   142,306.39x = 196,375.15 × 78,640.39
4. Step 4: Simplify right side
   142,306.39x = 15,443,018,382.31
5. Step 5: Solve for x
   x = 15,443,018,382.31/142,306.39
6. Step 6: Final answer
   x = 108,519.50