Finding the Fourth Proportional to 13,105.57, 18,085.76 and 7,137.40

Step by Step Solution

1. Step 1: Write the proportion equation
   13,105.57 : 18,085.76 = 7,137.40 : x
2. Step 2: Convert to fraction form
   13,105.57/18,085.76 = 7,137.40/x
3. Step 3: Cross multiply
   13,105.57x = 18,085.76 × 7,137.40
4. Step 4: Simplify right side
   13,105.57x = 129,085,303.42
5. Step 5: Solve for x
   x = 129,085,303.42/13,105.57
6. Step 6: Final answer
   x = 9,849.65