Finding the Fourth Proportional to 21,138.52, 29,171.46 and 12,185.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,138.52 : 29,171.46 = 12,185.86 : x
2. Step 2: Convert to fraction form
   21,138.52/29,171.46 = 12,185.86/x
3. Step 3: Cross multiply
   21,138.52x = 29,171.46 × 12,185.86
4. Step 4: Simplify right side
   21,138.52x = 355,479,327.56
5. Step 5: Solve for x
   x = 355,479,327.56/21,138.52
6. Step 6: Final answer
   x = 16,816.66