Finding the Fourth Proportional to 13,139.55, 18,132.72 and 7,171.32

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.55 : 18,132.72 = 7,171.32 : x
2. Step 2: Convert to fraction form
   13,139.55/18,132.72 = 7,171.32/x
3. Step 3: Cross multiply
   13,139.55x = 18,132.72 × 7,171.32
4. Step 4: Simplify right side
   13,139.55x = 130,035,603.62
5. Step 5: Solve for x
   x = 130,035,603.62/13,139.55
6. Step 6: Final answer
   x = 9,896.50