Finding the Fourth Proportional to 8,111.39, 12,168.32 and 3,431.40

Step by Step Solution

1. Step 1: Write the proportion equation
   8,111.39 : 12,168.32 = 3,431.40 : x
2. Step 2: Convert to fraction form
   8,111.39/12,168.32 = 3,431.40/x
3. Step 3: Cross multiply
   8,111.39x = 12,168.32 × 3,431.40
4. Step 4: Simplify right side
   8,111.39x = 41,754,356.09
5. Step 5: Solve for x
   x = 41,754,356.09/8,111.39
6. Step 6: Final answer
   x = 5,147.62