Finding the Third Proportional to 258,578 and 401,799

Step by Step Solution

1. Step 1: Write the proportion equation
   258,578 : 401,799 = 401,799 : x
2. Step 2: Convert to fraction form
   258,578/401,799 = 401,799/x
3. Step 3: Cross multiply
   258,578x = 401,799 × 401,799
4. Step 4: Simplify right side
   258,578x = 161,442,436,401
5. Step 5: Solve for x
   x = 161,442,436,401/258,578
6. Step 6: Final answer
   x = 624,347.15