Finding the Fourth Proportional to 8,111.31, 12,168.81 and 3,431.72

Step by Step Solution

1. Step 1: Write the proportion equation
   8,111.31 : 12,168.81 = 3,431.72 : x
2. Step 2: Convert to fraction form
   8,111.31/12,168.81 = 3,431.72/x
3. Step 3: Cross multiply
   8,111.31x = 12,168.81 × 3,431.72
4. Step 4: Simplify right side
   8,111.31x = 41,759,887.81
5. Step 5: Solve for x
   x = 41,759,887.81/8,111.31
6. Step 6: Final answer
   x = 5,148.35