Finding the Fourth Proportional to 8,081.49, 12,129.57 and 3,405

Step by Step Solution

1. Step 1: Write the proportion equation
   8,081.49 : 12,129.57 = 3,405 : x
2. Step 2: Convert to fraction form
   8,081.49/12,129.57 = 3,405/x
3. Step 3: Cross multiply
   8,081.49x = 12,129.57 × 3,405
4. Step 4: Simplify right side
   8,081.49x = 41,301,185.85
5. Step 5: Solve for x
   x = 41,301,185.85/8,081.49
6. Step 6: Final answer
   x = 5,110.59