Finding the Fourth Proportional to 21,133.59, 31,672.90 and 8,639.34

Step by Step Solution

1. Step 1: Write the proportion equation
   21,133.59 : 31,672.90 = 8,639.34 : x
2. Step 2: Convert to fraction form
   21,133.59/31,672.90 = 8,639.34/x
3. Step 3: Cross multiply
   21,133.59x = 31,672.90 × 8,639.34
4. Step 4: Simplify right side
   21,133.59x = 273,632,951.89
5. Step 5: Solve for x
   x = 273,632,951.89/21,133.59
6. Step 6: Final answer
   x = 12,947.77