Finding the Third Proportional to 399,309 and 603,124.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,309 : 603,124.50 = 603,124.50 : x
2. Step 2: Convert to fraction form
   399,309/603,124.50 = 603,124.50/x
3. Step 3: Cross multiply
   399,309x = 603,124.50 × 603,124.50
4. Step 4: Simplify right side
   399,309x = 363,759,162,500.25
5. Step 5: Solve for x
   x = 363,759,162,500.25/399,309
6. Step 6: Final answer
   x = 910,971.61