Finding the Fourth Proportional to 21,456.24, 29,609.73 and 12,956.56

Step by Step Solution

1. Step 1: Write the proportion equation
   21,456.24 : 29,609.73 = 12,956.56 : x
2. Step 2: Convert to fraction form
   21,456.24/29,609.73 = 12,956.56/x
3. Step 3: Cross multiply
   21,456.24x = 29,609.73 × 12,956.56
4. Step 4: Simplify right side
   21,456.24x = 383,640,243.33
5. Step 5: Solve for x
   x = 383,640,243.33/21,456.24
6. Step 6: Final answer
   x = 17,880.12