Finding the Third Proportional to 309,640 and 478,554

Step by Step Solution

1. Step 1: Write the proportion equation
   309,640 : 478,554 = 478,554 : x
2. Step 2: Convert to fraction form
   309,640/478,554 = 478,554/x
3. Step 3: Cross multiply
   309,640x = 478,554 × 478,554
4. Step 4: Simplify right side
   309,640x = 229,013,930,916
5. Step 5: Solve for x
   x = 229,013,930,916/309,640
6. Step 6: Final answer
   x = 739,613.52