Finding the Fourth Proportional to 142,339.50, 196,428.75 and 78,677.30

Step by Step Solution

1. Step 1: Write the proportion equation
   142,339.50 : 196,428.75 = 78,677.30 : x
2. Step 2: Convert to fraction form
   142,339.50/196,428.75 = 78,677.30/x
3. Step 3: Cross multiply
   142,339.50x = 196,428.75 × 78,677.30
4. Step 4: Simplify right side
   142,339.50x = 15,454,482,783.50
5. Step 5: Solve for x
   x = 15,454,482,783.50/142,339.50
6. Step 6: Final answer
   x = 108,574.80