Finding the Fourth Proportional to 71,689.52, 98,928.72 and 39,856.10

Step by Step Solution

1. Step 1: Write the proportion equation
   71,689.52 : 98,928.72 = 39,856.10 : x
2. Step 2: Convert to fraction form
   71,689.52/98,928.72 = 39,856.10/x
3. Step 3: Cross multiply
   71,689.52x = 98,928.72 × 39,856.10
4. Step 4: Simplify right side
   71,689.52x = 3,942,912,957.19
5. Step 5: Solve for x
   x = 3,942,912,957.19/71,689.52
6. Step 6: Final answer
   x = 54,999.85