Finding the Fourth Proportional to 13,105.78, 18,085.56 and 7,137.38

Step by Step Solution

1. Step 1: Write the proportion equation
   13,105.78 : 18,085.56 = 7,137.38 : x
2. Step 2: Convert to fraction form
   13,105.78/18,085.56 = 7,137.38/x
3. Step 3: Cross multiply
   13,105.78x = 18,085.56 × 7,137.38
4. Step 4: Simplify right side
   13,105.78x = 129,083,514.23
5. Step 5: Solve for x
   x = 129,083,514.23/13,105.78
6. Step 6: Final answer
   x = 9,849.36