Finding the Third Proportional to 405,894 and 646,429

Step by Step Solution

1. Step 1: Write the proportion equation
   405,894 : 646,429 = 646,429 : x
2. Step 2: Convert to fraction form
   405,894/646,429 = 646,429/x
3. Step 3: Cross multiply
   405,894x = 646,429 × 646,429
4. Step 4: Simplify right side
   405,894x = 417,870,452,041
5. Step 5: Solve for x
   x = 417,870,452,041/405,894
6. Step 6: Final answer
   x = 1,029,506.35