Finding the Third Proportional to 400,801.50 and 639,112.50

Step by Step Solution

1. Step 1: Write the proportion equation
   400,801.50 : 639,112.50 = 639,112.50 : x
2. Step 2: Convert to fraction form
   400,801.50/639,112.50 = 639,112.50/x
3. Step 3: Cross multiply
   400,801.50x = 639,112.50 × 639,112.50
4. Step 4: Simplify right side
   400,801.50x = 408,464,787,656.25
5. Step 5: Solve for x
   x = 408,464,787,656.25/400,801.50
6. Step 6: Final answer
   x = 1,019,119.91