Finding the Third Proportional to 290,728 and 643,632

Step by Step Solution

1. Step 1: Write the proportion equation
   290,728 : 643,632 = 643,632 : x
2. Step 2: Convert to fraction form
   290,728/643,632 = 643,632/x
3. Step 3: Cross multiply
   290,728x = 643,632 × 643,632
4. Step 4: Simplify right side
   290,728x = 414,262,151,424
5. Step 5: Solve for x
   x = 414,262,151,424/290,728
6. Step 6: Final answer
   x = 1,424,913.15