Finding the Third Proportional to 3,989,331 and 8,499,978

Step by Step Solution

1. Step 1: Write the proportion equation
   3,989,331 : 8,499,978 = 8,499,978 : x
2. Step 2: Convert to fraction form
   3,989,331/8,499,978 = 8,499,978/x
3. Step 3: Cross multiply
   3,989,331x = 8,499,978 × 8,499,978
4. Step 4: Simplify right side
   3,989,331x = 72,249,626,000,484
5. Step 5: Solve for x
   x = 72,249,626,000,484/3,989,331
6. Step 6: Final answer
   x = 18,110,712.30