Finding the Third Proportional to 298,790 and 642,892

Step by Step Solution

1. Step 1: Write the proportion equation
   298,790 : 642,892 = 642,892 : x
2. Step 2: Convert to fraction form
   298,790/642,892 = 642,892/x
3. Step 3: Cross multiply
   298,790x = 642,892 × 642,892
4. Step 4: Simplify right side
   298,790x = 413,310,123,664
5. Step 5: Solve for x
   x = 413,310,123,664/298,790
6. Step 6: Final answer
   x = 1,383,279.64