Finding the Fourth Proportional to 21,099.83, 29,120.51 and 12,147.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,099.83 : 29,120.51 = 12,147.71 : x
2. Step 2: Convert to fraction form
   21,099.83/29,120.51 = 12,147.71/x
3. Step 3: Cross multiply
   21,099.83x = 29,120.51 × 12,147.71
4. Step 4: Simplify right side
   21,099.83x = 353,747,395.30
5. Step 5: Solve for x
   x = 353,747,395.30/21,099.83
6. Step 6: Final answer
   x = 16,765.42