Finding the Third Proportional to 639,856 and 1,400,240

Step by Step Solution

1. Step 1: Write the proportion equation
   639,856 : 1,400,240 = 1,400,240 : x
2. Step 2: Convert to fraction form
   639,856/1,400,240 = 1,400,240/x
3. Step 3: Cross multiply
   639,856x = 1,400,240 × 1,400,240
4. Step 4: Simplify right side
   639,856x = 1,960,672,057,600
5. Step 5: Solve for x
   x = 1,960,672,057,600/639,856
6. Step 6: Final answer
   x = 3,064,239.54