Finding the Fourth Proportional to 12,840.31, 17,719.73 and 7,251.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,840.31 : 17,719.73 = 7,251.31 : x
2. Step 2: Convert to fraction form
   12,840.31/17,719.73 = 7,251.31/x
3. Step 3: Cross multiply
   12,840.31x = 17,719.73 × 7,251.31
4. Step 4: Simplify right side
   12,840.31x = 128,491,255.35
5. Step 5: Solve for x
   x = 128,491,255.35/12,840.31
6. Step 6: Final answer
   x = 10,006.87