Finding the Third Proportional to 300,411 and 643,468

Step by Step Solution

1. Step 1: Write the proportion equation
   300,411 : 643,468 = 643,468 : x
2. Step 2: Convert to fraction form
   300,411/643,468 = 643,468/x
3. Step 3: Cross multiply
   300,411x = 643,468 × 643,468
4. Step 4: Simplify right side
   300,411x = 414,051,067,024
5. Step 5: Solve for x
   x = 414,051,067,024/300,411
6. Step 6: Final answer
   x = 1,378,281.98