Finding the Fourth Proportional to 10,540.56, 15,729 and 9,140.88

Step by Step Solution

1. Step 1: Write the proportion equation
   10,540.56 : 15,729 = 9,140.88 : x
2. Step 2: Convert to fraction form
   10,540.56/15,729 = 9,140.88/x
3. Step 3: Cross multiply
   10,540.56x = 15,729 × 9,140.88
4. Step 4: Simplify right side
   10,540.56x = 143,776,901.52
5. Step 5: Solve for x
   x = 143,776,901.52/10,540.56
6. Step 6: Final answer
   x = 13,640.35