Finding the Fourth Proportional to 12,909.15, 19,361.41 and 8,215.23

Step by Step Solution

1. Step 1: Write the proportion equation
   12,909.15 : 19,361.41 = 8,215.23 : x
2. Step 2: Convert to fraction form
   12,909.15/19,361.41 = 8,215.23/x
3. Step 3: Cross multiply
   12,909.15x = 19,361.41 × 8,215.23
4. Step 4: Simplify right side
   12,909.15x = 159,058,436.27
5. Step 5: Solve for x
   x = 159,058,436.27/12,909.15
6. Step 6: Final answer
   x = 12,321.37