Finding the Fourth Proportional to 8,128.31, 12,186.99 and 3,449.34

Step by Step Solution

1. Step 1: Write the proportion equation
   8,128.31 : 12,186.99 = 3,449.34 : x
2. Step 2: Convert to fraction form
   8,128.31/12,186.99 = 3,449.34/x
3. Step 3: Cross multiply
   8,128.31x = 12,186.99 × 3,449.34
4. Step 4: Simplify right side
   8,128.31x = 42,037,072.09
5. Step 5: Solve for x
   x = 42,037,072.09/8,128.31
6. Step 6: Final answer
   x = 5,171.69