Finding the Third Proportional to 292,870 and 639,443

Step by Step Solution

1. Step 1: Write the proportion equation
   292,870 : 639,443 = 639,443 : x
2. Step 2: Convert to fraction form
   292,870/639,443 = 639,443/x
3. Step 3: Cross multiply
   292,870x = 639,443 × 639,443
4. Step 4: Simplify right side
   292,870x = 408,887,350,249
5. Step 5: Solve for x
   x = 408,887,350,249/292,870
6. Step 6: Final answer
   x = 1,396,139.41