Finding the Fourth Proportional to 13,109.55, 18,091.22 and 7,141.20

Step by Step Solution

1. Step 1: Write the proportion equation
   13,109.55 : 18,091.22 = 7,141.20 : x
2. Step 2: Convert to fraction form
   13,109.55/18,091.22 = 7,141.20/x
3. Step 3: Cross multiply
   13,109.55x = 18,091.22 × 7,141.20
4. Step 4: Simplify right side
   13,109.55x = 129,192,984.56
5. Step 5: Solve for x
   x = 129,192,984.56/13,109.55
6. Step 6: Final answer
   x = 9,854.88