Finding the Third Proportional to 8,438 and 13,116

Step by Step Solution

1. Step 1: Write the proportion equation
   8,438 : 13,116 = 13,116 : x
2. Step 2: Convert to fraction form
   8,438/13,116 = 13,116/x
3. Step 3: Cross multiply
   8,438x = 13,116 × 13,116
4. Step 4: Simplify right side
   8,438x = 172,029,456
5. Step 5: Solve for x
   x = 172,029,456/8,438
6. Step 6: Final answer
   x = 20,387.47