Finding the Third Proportional to 296,607 and 639,870

Step by Step Solution

1. Step 1: Write the proportion equation
   296,607 : 639,870 = 639,870 : x
2. Step 2: Convert to fraction form
   296,607/639,870 = 639,870/x
3. Step 3: Cross multiply
   296,607x = 639,870 × 639,870
4. Step 4: Simplify right side
   296,607x = 409,433,616,900
5. Step 5: Solve for x
   x = 409,433,616,900/296,607
6. Step 6: Final answer
   x = 1,380,390.94