Finding the Third Proportional to 405,687 and 636,381.50

Step by Step Solution

1. Step 1: Write the proportion equation
   405,687 : 636,381.50 = 636,381.50 : x
2. Step 2: Convert to fraction form
   405,687/636,381.50 = 636,381.50/x
3. Step 3: Cross multiply
   405,687x = 636,381.50 × 636,381.50
4. Step 4: Simplify right side
   405,687x = 404,981,413,542.25
5. Step 5: Solve for x
   x = 404,981,413,542.25/405,687
6. Step 6: Final answer
   x = 998,260.76