Finding the Fourth Proportional to 13,139.56, 18,132.31 and 7,171.35

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.56 : 18,132.31 = 7,171.35 : x
2. Step 2: Convert to fraction form
   13,139.56/18,132.31 = 7,171.35/x
3. Step 3: Cross multiply
   13,139.56x = 18,132.31 × 7,171.35
4. Step 4: Simplify right side
   13,139.56x = 130,033,141.32
5. Step 5: Solve for x
   x = 130,033,141.32/13,139.56
6. Step 6: Final answer
   x = 9,896.31