Finding the Fourth Proportional to 21,639.15, 29,863.89 and 12,081.15

Step by Step Solution

1. Step 1: Write the proportion equation
   21,639.15 : 29,863.89 = 12,081.15 : x
2. Step 2: Convert to fraction form
   21,639.15/29,863.89 = 12,081.15/x
3. Step 3: Cross multiply
   21,639.15x = 29,863.89 × 12,081.15
4. Step 4: Simplify right side
   21,639.15x = 360,790,134.67
5. Step 5: Solve for x
   x = 360,790,134.67/21,639.15
6. Step 6: Final answer
   x = 16,673.03