Finding the Third Proportional to 383,691 and 639,446.25

Step by Step Solution

1. Step 1: Write the proportion equation
   383,691 : 639,446.25 = 639,446.25 : x
2. Step 2: Convert to fraction form
   383,691/639,446.25 = 639,446.25/x
3. Step 3: Cross multiply
   383,691x = 639,446.25 × 639,446.25
4. Step 4: Simplify right side
   383,691x = 408,891,506,639.06
5. Step 5: Solve for x
   x = 408,891,506,639.06/383,691
6. Step 6: Final answer
   x = 1,065,679.17