Finding the Fourth Proportional to 13,106.13, 18,086.78 and 7,138.12

Step by Step Solution

1. Step 1: Write the proportion equation
   13,106.13 : 18,086.78 = 7,138.12 : x
2. Step 2: Convert to fraction form
   13,106.13/18,086.78 = 7,138.12/x
3. Step 3: Cross multiply
   13,106.13x = 18,086.78 × 7,138.12
4. Step 4: Simplify right side
   13,106.13x = 129,105,606.05
5. Step 5: Solve for x
   x = 129,105,606.05/13,106.13
6. Step 6: Final answer
   x = 9,850.78