Finding the Fourth Proportional to 12,839.78, 17,709.41 and 8,119.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,839.78 : 17,709.41 = 8,119.50 : x
2. Step 2: Convert to fraction form
   12,839.78/17,709.41 = 8,119.50/x
3. Step 3: Cross multiply
   12,839.78x = 17,709.41 × 8,119.50
4. Step 4: Simplify right side
   12,839.78x = 143,791,554.50
5. Step 5: Solve for x
   x = 143,791,554.50/12,839.78
6. Step 6: Final answer
   x = 11,198.91