Finding the Fourth Proportional to 21,667.88, 29,910.88 and 13,172.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,667.88 : 29,910.88 = 13,172.71 : x
2. Step 2: Convert to fraction form
   21,667.88/29,910.88 = 13,172.71/x
3. Step 3: Cross multiply
   21,667.88x = 29,910.88 × 13,172.71
4. Step 4: Simplify right side
   21,667.88x = 394,007,440.97
5. Step 5: Solve for x
   x = 394,007,440.97/21,667.88
6. Step 6: Final answer
   x = 18,183.94