Finding the Fourth Proportional to 22,721.72, 31,355.90 and 12,649.90

Step by Step Solution

1. Step 1: Write the proportion equation
   22,721.72 : 31,355.90 = 12,649.90 : x
2. Step 2: Convert to fraction form
   22,721.72/31,355.90 = 12,649.90/x
3. Step 3: Cross multiply
   22,721.72x = 31,355.90 × 12,649.90
4. Step 4: Simplify right side
   22,721.72x = 396,648,956.43
5. Step 5: Solve for x
   x = 396,648,956.43/22,721.72
6. Step 6: Final answer
   x = 17,456.82