Finding the Third Proportional to 8,399 and 12,339

Step by Step Solution

1. Step 1: Write the proportion equation
   8,399 : 12,339 = 12,339 : x
2. Step 2: Convert to fraction form
   8,399/12,339 = 12,339/x
3. Step 3: Cross multiply
   8,399x = 12,339 × 12,339
4. Step 4: Simplify right side
   8,399x = 152,250,921
5. Step 5: Solve for x
   x = 152,250,921/8,399
6. Step 6: Final answer
   x = 18,127.27