Finding the Fourth Proportional to 13,139.51, 18,132.91 and 7,171.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.51 : 18,132.91 = 7,171.57 : x
2. Step 2: Convert to fraction form
   13,139.51/18,132.91 = 7,171.57/x
3. Step 3: Cross multiply
   13,139.51x = 18,132.91 × 7,171.57
4. Step 4: Simplify right side
   13,139.51x = 130,041,433.37
5. Step 5: Solve for x
   x = 130,041,433.37/13,139.51
6. Step 6: Final answer
   x = 9,896.98