Finding the Third Proportional to 639,384 and 1,378,488

Step by Step Solution

1. Step 1: Write the proportion equation
   639,384 : 1,378,488 = 1,378,488 : x
2. Step 2: Convert to fraction form
   639,384/1,378,488 = 1,378,488/x
3. Step 3: Cross multiply
   639,384x = 1,378,488 × 1,378,488
4. Step 4: Simplify right side
   639,384x = 1,900,229,166,144
5. Step 5: Solve for x
   x = 1,900,229,166,144/639,384
6. Step 6: Final answer
   x = 2,971,968.59