Finding the Third Proportional to 12,720 and 21,384

Step by Step Solution

1. Step 1: Write the proportion equation
   12,720 : 21,384 = 21,384 : x
2. Step 2: Convert to fraction form
   12,720/21,384 = 21,384/x
3. Step 3: Cross multiply
   12,720x = 21,384 × 21,384
4. Step 4: Simplify right side
   12,720x = 457,275,456
5. Step 5: Solve for x
   x = 457,275,456/12,720
6. Step 6: Final answer
   x = 35,949.33