Finding the Third Proportional to 321,548 and 687,388

Step by Step Solution

1. Step 1: Write the proportion equation
   321,548 : 687,388 = 687,388 : x
2. Step 2: Convert to fraction form
   321,548/687,388 = 687,388/x
3. Step 3: Cross multiply
   321,548x = 687,388 × 687,388
4. Step 4: Simplify right side
   321,548x = 472,502,262,544
5. Step 5: Solve for x
   x = 472,502,262,544/321,548
6. Step 6: Final answer
   x = 1,469,461.05