Finding the Fourth Proportional to 12,405.72, 17,124.30 and 8,215.32

Step by Step Solution

1. Step 1: Write the proportion equation
   12,405.72 : 17,124.30 = 8,215.32 : x
2. Step 2: Convert to fraction form
   12,405.72/17,124.30 = 8,215.32/x
3. Step 3: Cross multiply
   12,405.72x = 17,124.30 × 8,215.32
4. Step 4: Simplify right side
   12,405.72x = 140,681,604.28
5. Step 5: Solve for x
   x = 140,681,604.28/12,405.72
6. Step 6: Final answer
   x = 11,340.06