Finding the Third Proportional to 300,412 and 643,472

Step by Step Solution

1. Step 1: Write the proportion equation
   300,412 : 643,472 = 643,472 : x
2. Step 2: Convert to fraction form
   300,412/643,472 = 643,472/x
3. Step 3: Cross multiply
   300,412x = 643,472 × 643,472
4. Step 4: Simplify right side
   300,412x = 414,056,214,784
5. Step 5: Solve for x
   x = 414,056,214,784/300,412
6. Step 6: Final answer
   x = 1,378,294.52