Finding the Third Proportional to 428,628 and 646,830

Step by Step Solution

1. Step 1: Write the proportion equation
   428,628 : 646,830 = 646,830 : x
2. Step 2: Convert to fraction form
   428,628/646,830 = 646,830/x
3. Step 3: Cross multiply
   428,628x = 646,830 × 646,830
4. Step 4: Simplify right side
   428,628x = 418,389,048,900
5. Step 5: Solve for x
   x = 418,389,048,900/428,628
6. Step 6: Final answer
   x = 976,112.27