Finding the Third Proportional to 258,288 and 387,696

Step by Step Solution

1. Step 1: Write the proportion equation
   258,288 : 387,696 = 387,696 : x
2. Step 2: Convert to fraction form
   258,288/387,696 = 387,696/x
3. Step 3: Cross multiply
   258,288x = 387,696 × 387,696
4. Step 4: Simplify right side
   258,288x = 150,308,188,416
5. Step 5: Solve for x
   x = 150,308,188,416/258,288
6. Step 6: Final answer
   x = 581,940.27