Finding the Third Proportional to 8,390 and 12,369

Step by Step Solution

1. Step 1: Write the proportion equation
   8,390 : 12,369 = 12,369 : x
2. Step 2: Convert to fraction form
   8,390/12,369 = 12,369/x
3. Step 3: Cross multiply
   8,390x = 12,369 × 12,369
4. Step 4: Simplify right side
   8,390x = 152,992,161
5. Step 5: Solve for x
   x = 152,992,161/8,390
6. Step 6: Final answer
   x = 18,235.06