Finding the Third Proportional to 400,830 and 639,150

Step by Step Solution

1. Step 1: Write the proportion equation
   400,830 : 639,150 = 639,150 : x
2. Step 2: Convert to fraction form
   400,830/639,150 = 639,150/x
3. Step 3: Cross multiply
   400,830x = 639,150 × 639,150
4. Step 4: Simplify right side
   400,830x = 408,512,722,500
5. Step 5: Solve for x
   x = 408,512,722,500/400,830
6. Step 6: Final answer
   x = 1,019,167.03