Finding the Fourth Proportional to 78,665.20, 108,557.78 and 42,855.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78,665.20 : 108,557.78 = 42,855.50 : x
2. Step 2: Convert to fraction form
   78,665.20/108,557.78 = 42,855.50/x
3. Step 3: Cross multiply
   78,665.20x = 108,557.78 × 42,855.50
4. Step 4: Simplify right side
   78,665.20x = 4,652,297,940.79
5. Step 5: Solve for x
   x = 4,652,297,940.79/78,665.20
6. Step 6: Final answer
   x = 59,140.48