Finding the Third Proportional to 8,436 and 12,680

Step by Step Solution

1. Step 1: Write the proportion equation
   8,436 : 12,680 = 12,680 : x
2. Step 2: Convert to fraction form
   8,436/12,680 = 12,680/x
3. Step 3: Cross multiply
   8,436x = 12,680 × 12,680
4. Step 4: Simplify right side
   8,436x = 160,782,400
5. Step 5: Solve for x
   x = 160,782,400/8,436
6. Step 6: Final answer
   x = 19,059.08