Finding the Fourth Proportional to 72,139.36, 99,554.52 and 40,309.60

Step by Step Solution

1. Step 1: Write the proportion equation
   72,139.36 : 99,554.52 = 40,309.60 : x
2. Step 2: Convert to fraction form
   72,139.36/99,554.52 = 40,309.60/x
3. Step 3: Cross multiply
   72,139.36x = 99,554.52 × 40,309.60
4. Step 4: Simplify right side
   72,139.36x = 4,013,002,879.39
5. Step 5: Solve for x
   x = 4,013,002,879.39/72,139.36
6. Step 6: Final answer
   x = 55,628.48