Finding the Third Proportional to 5,387,978 and 8,365,299

Step by Step Solution

1. Step 1: Write the proportion equation
   5,387,978 : 8,365,299 = 8,365,299 : x
2. Step 2: Convert to fraction form
   5,387,978/8,365,299 = 8,365,299/x
3. Step 3: Cross multiply
   5,387,978x = 8,365,299 × 8,365,299
4. Step 4: Simplify right side
   5,387,978x = 69,978,227,359,401
5. Step 5: Solve for x
   x = 69,978,227,359,401/5,387,978
6. Step 6: Final answer
   x = 12,987,845.79