Finding the Third Proportional to 639,428 and 1,400,680

Step by Step Solution

1. Step 1: Write the proportion equation
   639,428 : 1,400,680 = 1,400,680 : x
2. Step 2: Convert to fraction form
   639,428/1,400,680 = 1,400,680/x
3. Step 3: Cross multiply
   639,428x = 1,400,680 × 1,400,680
4. Step 4: Simplify right side
   639,428x = 1,961,904,462,400
5. Step 5: Solve for x
   x = 1,961,904,462,400/639,428
6. Step 6: Final answer
   x = 3,068,217.94