Finding the Fourth Proportional to 8,405.98, 12,607.48 and 3,139.81

Step by Step Solution

1. Step 1: Write the proportion equation
   8,405.98 : 12,607.48 = 3,139.81 : x
2. Step 2: Convert to fraction form
   8,405.98/12,607.48 = 3,139.81/x
3. Step 3: Cross multiply
   8,405.98x = 12,607.48 × 3,139.81
4. Step 4: Simplify right side
   8,405.98x = 39,585,091.78
5. Step 5: Solve for x
   x = 39,585,091.78/8,405.98
6. Step 6: Final answer
   x = 4,709.16