Finding the Third Proportional to 388,332 and 521,505

Step by Step Solution

1. Step 1: Write the proportion equation
   388,332 : 521,505 = 521,505 : x
2. Step 2: Convert to fraction form
   388,332/521,505 = 521,505/x
3. Step 3: Cross multiply
   388,332x = 521,505 × 521,505
4. Step 4: Simplify right side
   388,332x = 271,967,465,025
5. Step 5: Solve for x
   x = 271,967,465,025/388,332
6. Step 6: Final answer
   x = 700,347.81