Finding the Third Proportional to 321,640 and 687,544.50

Step by Step Solution

1. Step 1: Write the proportion equation
   321,640 : 687,544.50 = 687,544.50 : x
2. Step 2: Convert to fraction form
   321,640/687,544.50 = 687,544.50/x
3. Step 3: Cross multiply
   321,640x = 687,544.50 × 687,544.50
4. Step 4: Simplify right side
   321,640x = 472,717,439,480.25
5. Step 5: Solve for x
   x = 472,717,439,480.25/321,640
6. Step 6: Final answer
   x = 1,469,709.74