Finding the Third Proportional to 398,640 and 617,886

Step by Step Solution

1. Step 1: Write the proportion equation
   398,640 : 617,886 = 617,886 : x
2. Step 2: Convert to fraction form
   398,640/617,886 = 617,886/x
3. Step 3: Cross multiply
   398,640x = 617,886 × 617,886
4. Step 4: Simplify right side
   398,640x = 381,783,108,996
5. Step 5: Solve for x
   x = 381,783,108,996/398,640
6. Step 6: Final answer
   x = 957,714.00