Finding the Third Proportional to 291,917 and 621,499

Step by Step Solution

1. Step 1: Write the proportion equation
   291,917 : 621,499 = 621,499 : x
2. Step 2: Convert to fraction form
   291,917/621,499 = 621,499/x
3. Step 3: Cross multiply
   291,917x = 621,499 × 621,499
4. Step 4: Simplify right side
   291,917x = 386,261,007,001
5. Step 5: Solve for x
   x = 386,261,007,001/291,917
6. Step 6: Final answer
   x = 1,323,187.78