Finding the Third Proportional to 639,128 and 1,392,660

Step by Step Solution

1. Step 1: Write the proportion equation
   639,128 : 1,392,660 = 1,392,660 : x
2. Step 2: Convert to fraction form
   639,128/1,392,660 = 1,392,660/x
3. Step 3: Cross multiply
   639,128x = 1,392,660 × 1,392,660
4. Step 4: Simplify right side
   639,128x = 1,939,501,875,600
5. Step 5: Solve for x
   x = 1,939,501,875,600/639,128
6. Step 6: Final answer
   x = 3,034,606.33