Finding the Fourth Proportional to 12,406.74, 18,607.59 and 3,639.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,406.74 : 18,607.59 = 3,639.30 : x
2. Step 2: Convert to fraction form
   12,406.74/18,607.59 = 3,639.30/x
3. Step 3: Cross multiply
   12,406.74x = 18,607.59 × 3,639.30
4. Step 4: Simplify right side
   12,406.74x = 67,718,602.29
5. Step 5: Solve for x
   x = 67,718,602.29/12,406.74
6. Step 6: Final answer
   x = 5,458.21