Finding the Third Proportional to 399,570 and 603,499.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,570 : 603,499.50 = 603,499.50 : x
2. Step 2: Convert to fraction form
   399,570/603,499.50 = 603,499.50/x
3. Step 3: Cross multiply
   399,570x = 603,499.50 × 603,499.50
4. Step 4: Simplify right side
   399,570x = 364,211,646,500.25
5. Step 5: Solve for x
   x = 364,211,646,500.25/399,570
6. Step 6: Final answer
   x = 911,508.99