Finding the Fourth Proportional to 21,057.71, 29,057.43 and 12,106.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,057.71 : 29,057.43 = 12,106.50 : x
2. Step 2: Convert to fraction form
   21,057.71/29,057.43 = 12,106.50/x
3. Step 3: Cross multiply
   21,057.71x = 29,057.43 × 12,106.50
4. Step 4: Simplify right side
   21,057.71x = 351,783,712.73
5. Step 5: Solve for x
   x = 351,783,712.73/21,057.71
6. Step 6: Final answer
   x = 16,705.70