Finding the Third Proportional to 256,428 and 398,083.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,428 : 398,083.50 = 398,083.50 : x
2. Step 2: Convert to fraction form
   256,428/398,083.50 = 398,083.50/x
3. Step 3: Cross multiply
   256,428x = 398,083.50 × 398,083.50
4. Step 4: Simplify right side
   256,428x = 158,470,472,972.25
5. Step 5: Solve for x
   x = 158,470,472,972.25/256,428
6. Step 6: Final answer
   x = 617,992.08