Finding the Third Proportional to 298,158 and 638,920.50

Step by Step Solution

1. Step 1: Write the proportion equation
   298,158 : 638,920.50 = 638,920.50 : x
2. Step 2: Convert to fraction form
   298,158/638,920.50 = 638,920.50/x
3. Step 3: Cross multiply
   298,158x = 638,920.50 × 638,920.50
4. Step 4: Simplify right side
   298,158x = 408,219,405,320.25
5. Step 5: Solve for x
   x = 408,219,405,320.25/298,158
6. Step 6: Final answer
   x = 1,369,137.86