Finding the Third Proportional to 328,640 and 672,856

Step by Step Solution

1. Step 1: Write the proportion equation
   328,640 : 672,856 = 672,856 : x
2. Step 2: Convert to fraction form
   328,640/672,856 = 672,856/x
3. Step 3: Cross multiply
   328,640x = 672,856 × 672,856
4. Step 4: Simplify right side
   328,640x = 452,735,196,736
5. Step 5: Solve for x
   x = 452,735,196,736/328,640
6. Step 6: Final answer
   x = 1,377,602.23