Finding the Fourth Proportional to 21,164.88, 31,744.72 and 12,285.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,164.88 : 31,744.72 = 12,285.05 : x
2. Step 2: Convert to fraction form
   21,164.88/31,744.72 = 12,285.05/x
3. Step 3: Cross multiply
   21,164.88x = 31,744.72 × 12,285.05
4. Step 4: Simplify right side
   21,164.88x = 389,985,329.07
5. Step 5: Solve for x
   x = 389,985,329.07/21,164.88
6. Step 6: Final answer
   x = 18,426.06