Finding the Third Proportional to 8,436 and 13,405

Step by Step Solution

1. Step 1: Write the proportion equation
   8,436 : 13,405 = 13,405 : x
2. Step 2: Convert to fraction form
   8,436/13,405 = 13,405/x
3. Step 3: Cross multiply
   8,436x = 13,405 × 13,405
4. Step 4: Simplify right side
   8,436x = 179,694,025
5. Step 5: Solve for x
   x = 179,694,025/8,436
6. Step 6: Final answer
   x = 21,300.86