Finding the Third Proportional to 12,720 and 19,799

Step by Step Solution

1. Step 1: Write the proportion equation
   12,720 : 19,799 = 19,799 : x
2. Step 2: Convert to fraction form
   12,720/19,799 = 19,799/x
3. Step 3: Cross multiply
   12,720x = 19,799 × 19,799
4. Step 4: Simplify right side
   12,720x = 392,000,401
5. Step 5: Solve for x
   x = 392,000,401/12,720
6. Step 6: Final answer
   x = 30,817.64