Finding the Third Proportional to 199,128.50 and 315,464.50

Step by Step Solution

1. Step 1: Write the proportion equation
   199,128.50 : 315,464.50 = 315,464.50 : x
2. Step 2: Convert to fraction form
   199,128.50/315,464.50 = 315,464.50/x
3. Step 3: Cross multiply
   199,128.50x = 315,464.50 × 315,464.50
4. Step 4: Simplify right side
   199,128.50x = 99,517,850,760.25
5. Step 5: Solve for x
   x = 99,517,850,760.25/199,128.50
6. Step 6: Final answer
   x = 499,766.99