Finding the Third Proportional to 309,042 and 641,770

Step by Step Solution

1. Step 1: Write the proportion equation
   309,042 : 641,770 = 641,770 : x
2. Step 2: Convert to fraction form
   309,042/641,770 = 641,770/x
3. Step 3: Cross multiply
   309,042x = 641,770 × 641,770
4. Step 4: Simplify right side
   309,042x = 411,868,732,900
5. Step 5: Solve for x
   x = 411,868,732,900/309,042
6. Step 6: Final answer
   x = 1,332,727.37