Finding the Fourth Proportional to 21,908.36, 30,233.40 and 12,960.29

Step by Step Solution

1. Step 1: Write the proportion equation
   21,908.36 : 30,233.40 = 12,960.29 : x
2. Step 2: Convert to fraction form
   21,908.36/30,233.40 = 12,960.29/x
3. Step 3: Cross multiply
   21,908.36x = 30,233.40 × 12,960.29
4. Step 4: Simplify right side
   21,908.36x = 391,833,631.69
5. Step 5: Solve for x
   x = 391,833,631.69/21,908.36
6. Step 6: Final answer
   x = 17,885.12