Finding the Third Proportional to 309,100 and 677,978

Step by Step Solution

1. Step 1: Write the proportion equation
   309,100 : 677,978 = 677,978 : x
2. Step 2: Convert to fraction form
   309,100/677,978 = 677,978/x
3. Step 3: Cross multiply
   309,100x = 677,978 × 677,978
4. Step 4: Simplify right side
   309,100x = 459,654,168,484
5. Step 5: Solve for x
   x = 459,654,168,484/309,100
6. Step 6: Final answer
   x = 1,487,072.69