Finding the Third Proportional to 418,309 and 646,357.50

Step by Step Solution

1. Step 1: Write the proportion equation
   418,309 : 646,357.50 = 646,357.50 : x
2. Step 2: Convert to fraction form
   418,309/646,357.50 = 646,357.50/x
3. Step 3: Cross multiply
   418,309x = 646,357.50 × 646,357.50
4. Step 4: Simplify right side
   418,309x = 417,778,017,806.25
5. Step 5: Solve for x
   x = 417,778,017,806.25/418,309
6. Step 6: Final answer
   x = 998,730.65