Finding the Third Proportional to 417,978 and 645,795

Step by Step Solution

1. Step 1: Write the proportion equation
   417,978 : 645,795 = 645,795 : x
2. Step 2: Convert to fraction form
   417,978/645,795 = 645,795/x
3. Step 3: Cross multiply
   417,978x = 645,795 × 645,795
4. Step 4: Simplify right side
   417,978x = 417,051,182,025
5. Step 5: Solve for x
   x = 417,051,182,025/417,978
6. Step 6: Final answer
   x = 997,782.62