Finding the Fourth Proportional to 13,140.56, 18,133.69 and 7,172.35

Step by Step Solution

1. Step 1: Write the proportion equation
   13,140.56 : 18,133.69 = 7,172.35 : x
2. Step 2: Convert to fraction form
   13,140.56/18,133.69 = 7,172.35/x
3. Step 3: Cross multiply
   13,140.56x = 18,133.69 × 7,172.35
4. Step 4: Simplify right side
   13,140.56x = 130,061,171.47
5. Step 5: Solve for x
   x = 130,061,171.47/13,140.56
6. Step 6: Final answer
   x = 9,897.69