Finding the Fourth Proportional to 71,789.57, 99,069.61 and 39,957.78

Step by Step Solution

1. Step 1: Write the proportion equation
   71,789.57 : 99,069.61 = 39,957.78 : x
2. Step 2: Convert to fraction form
   71,789.57/99,069.61 = 39,957.78/x
3. Step 3: Cross multiply
   71,789.57x = 99,069.61 × 39,957.78
4. Step 4: Simplify right side
   71,789.57x = 3,958,601,581.17
5. Step 5: Solve for x
   x = 3,958,601,581.17/71,789.57
6. Step 6: Final answer
   x = 55,141.74