Finding the Fourth Proportional to 72,172.30, 99,593.23 and 39,906.09

Step by Step Solution

1. Step 1: Write the proportion equation
   72,172.30 : 99,593.23 = 39,906.09 : x
2. Step 2: Convert to fraction form
   72,172.30/99,593.23 = 39,906.09/x
3. Step 3: Cross multiply
   72,172.30x = 99,593.23 × 39,906.09
4. Step 4: Simplify right side
   72,172.30x = 3,974,376,399.77
5. Step 5: Solve for x
   x = 3,974,376,399.77/72,172.30
6. Step 6: Final answer
   x = 55,067.89