Finding the Fourth Proportional to 12,406.72, 18,608.32 and 3,639.36

Step by Step Solution

1. Step 1: Write the proportion equation
   12,406.72 : 18,608.32 = 3,639.36 : x
2. Step 2: Convert to fraction form
   12,406.72/18,608.32 = 3,639.36/x
3. Step 3: Cross multiply
   12,406.72x = 18,608.32 × 3,639.36
4. Step 4: Simplify right side
   12,406.72x = 67,722,375.48
5. Step 5: Solve for x
   x = 67,722,375.48/12,406.72
6. Step 6: Final answer
   x = 5,458.52