Finding the Fourth Proportional to 142,338.78, 196,419.12 and 78,672.78

Step by Step Solution

1. Step 1: Write the proportion equation
   142,338.78 : 196,419.12 = 78,672.78 : x
2. Step 2: Convert to fraction form
   142,338.78/196,419.12 = 78,672.78/x
3. Step 3: Cross multiply
   142,338.78x = 196,419.12 × 78,672.78
4. Step 4: Simplify right side
   142,338.78x = 15,452,838,215.55
5. Step 5: Solve for x
   x = 15,452,838,215.55/142,338.78
6. Step 6: Final answer
   x = 108,563.80