Finding the Third Proportional to 421,103.81 and 647,920.69

Step by Step Solution

1. Step 1: Write the proportion equation
   421,103.81 : 647,920.69 = 647,920.69 : x
2. Step 2: Convert to fraction form
   421,103.81/647,920.69 = 647,920.69/x
3. Step 3: Cross multiply
   421,103.81x = 647,920.69 × 647,920.69
4. Step 4: Simplify right side
   421,103.81x = 419,801,217,290.47
5. Step 5: Solve for x
   x = 419,801,217,290.47/421,103.81
6. Step 6: Final answer
   x = 996,906.71