Finding the Fourth Proportional to 12,405.55, 18,610.14 and 3,639.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,405.55 : 18,610.14 = 3,639.31 : x
2. Step 2: Convert to fraction form
   12,405.55/18,610.14 = 3,639.31/x
3. Step 3: Cross multiply
   12,405.55x = 18,610.14 × 3,639.31
4. Step 4: Simplify right side
   12,405.55x = 67,728,068.60
5. Step 5: Solve for x
   x = 67,728,068.60/12,405.55
6. Step 6: Final answer
   x = 5,459.50