Finding the Third Proportional to 6,402 and 12,390

Step by Step Solution

1. Step 1: Write the proportion equation
   6,402 : 12,390 = 12,390 : x
2. Step 2: Convert to fraction form
   6,402/12,390 = 12,390/x
3. Step 3: Cross multiply
   6,402x = 12,390 × 12,390
4. Step 4: Simplify right side
   6,402x = 153,512,100
5. Step 5: Solve for x
   x = 153,512,100/6,402
6. Step 6: Final answer
   x = 23,978.77