Finding the Fourth Proportional to 21,105.88, 31,669.62 and 8,635.12

Step by Step Solution

1. Step 1: Write the proportion equation
   21,105.88 : 31,669.62 = 8,635.12 : x
2. Step 2: Convert to fraction form
   21,105.88/31,669.62 = 8,635.12/x
3. Step 3: Cross multiply
   21,105.88x = 31,669.62 × 8,635.12
4. Step 4: Simplify right side
   21,105.88x = 273,470,969.05
5. Step 5: Solve for x
   x = 273,470,969.05/21,105.88
6. Step 6: Final answer
   x = 12,957.10