Finding the Third Proportional to 256,576 and 398,248.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,576 : 398,248.50 = 398,248.50 : x
2. Step 2: Convert to fraction form
   256,576/398,248.50 = 398,248.50/x
3. Step 3: Cross multiply
   256,576x = 398,248.50 × 398,248.50
4. Step 4: Simplify right side
   256,576x = 158,601,867,752.25
5. Step 5: Solve for x
   x = 158,601,867,752.25/256,576
6. Step 6: Final answer
   x = 618,147.71