Finding the Third Proportional to 290,142 and 443,799

Step by Step Solution

1. Step 1: Write the proportion equation
   290,142 : 443,799 = 443,799 : x
2. Step 2: Convert to fraction form
   290,142/443,799 = 443,799/x
3. Step 3: Cross multiply
   290,142x = 443,799 × 443,799
4. Step 4: Simplify right side
   290,142x = 196,957,552,401
5. Step 5: Solve for x
   x = 196,957,552,401/290,142
6. Step 6: Final answer
   x = 678,831.58