Finding the Third Proportional to 6,390 and 10,638

Step by Step Solution

1. Step 1: Write the proportion equation
   6,390 : 10,638 = 10,638 : x
2. Step 2: Convert to fraction form
   6,390/10,638 = 10,638/x
3. Step 3: Cross multiply
   6,390x = 10,638 × 10,638
4. Step 4: Simplify right side
   6,390x = 113,167,044
5. Step 5: Solve for x
   x = 113,167,044/6,390
6. Step 6: Final answer
   x = 17,710.02