Finding the Third Proportional to 6,420 and 11,499

Step by Step Solution

1. Step 1: Write the proportion equation
   6,420 : 11,499 = 11,499 : x
2. Step 2: Convert to fraction form
   6,420/11,499 = 11,499/x
3. Step 3: Cross multiply
   6,420x = 11,499 × 11,499
4. Step 4: Simplify right side
   6,420x = 132,227,001
5. Step 5: Solve for x
   x = 132,227,001/6,420
6. Step 6: Final answer
   x = 20,596.11