Finding the Third Proportional to 8,309 and 12,980

Step by Step Solution

1. Step 1: Write the proportion equation
   8,309 : 12,980 = 12,980 : x
2. Step 2: Convert to fraction form
   8,309/12,980 = 12,980/x
3. Step 3: Cross multiply
   8,309x = 12,980 × 12,980
4. Step 4: Simplify right side
   8,309x = 168,480,400
5. Step 5: Solve for x
   x = 168,480,400/8,309
6. Step 6: Final answer
   x = 20,276.86