Finding the Third Proportional to 426,681 and 638,806.50

Step by Step Solution

1. Step 1: Write the proportion equation
   426,681 : 638,806.50 = 638,806.50 : x
2. Step 2: Convert to fraction form
   426,681/638,806.50 = 638,806.50/x
3. Step 3: Cross multiply
   426,681x = 638,806.50 × 638,806.50
4. Step 4: Simplify right side
   426,681x = 408,073,744,442.25
5. Step 5: Solve for x
   x = 408,073,744,442.25/426,681
6. Step 6: Final answer
   x = 956,390.71