Finding the Third Proportional to 408,134 and 643,499

Step by Step Solution

1. Step 1: Write the proportion equation
   408,134 : 643,499 = 643,499 : x
2. Step 2: Convert to fraction form
   408,134/643,499 = 643,499/x
3. Step 3: Cross multiply
   408,134x = 643,499 × 643,499
4. Step 4: Simplify right side
   408,134x = 414,090,963,001
5. Step 5: Solve for x
   x = 414,090,963,001/408,134
6. Step 6: Final answer
   x = 1,014,595.61