Finding the Third Proportional to 316,620 and 666,039

Step by Step Solution

1. Step 1: Write the proportion equation
   316,620 : 666,039 = 666,039 : x
2. Step 2: Convert to fraction form
   316,620/666,039 = 666,039/x
3. Step 3: Cross multiply
   316,620x = 666,039 × 666,039
4. Step 4: Simplify right side
   316,620x = 443,607,949,521
5. Step 5: Solve for x
   x = 443,607,949,521/316,620
6. Step 6: Final answer
   x = 1,401,073.68