Finding the Third Proportional to 405,418 and 635,978

Step by Step Solution

1. Step 1: Write the proportion equation
   405,418 : 635,978 = 635,978 : x
2. Step 2: Convert to fraction form
   405,418/635,978 = 635,978/x
3. Step 3: Cross multiply
   405,418x = 635,978 × 635,978
4. Step 4: Simplify right side
   405,418x = 404,468,016,484
5. Step 5: Solve for x
   x = 404,468,016,484/405,418
6. Step 6: Final answer
   x = 997,656.78