Finding the Third Proportional to 206,406 and 290,664.50

Step by Step Solution

1. Step 1: Write the proportion equation
   206,406 : 290,664.50 = 290,664.50 : x
2. Step 2: Convert to fraction form
   206,406/290,664.50 = 290,664.50/x
3. Step 3: Cross multiply
   206,406x = 290,664.50 × 290,664.50
4. Step 4: Simplify right side
   206,406x = 84,485,851,560.25
5. Step 5: Solve for x
   x = 84,485,851,560.25/206,406
6. Step 6: Final answer
   x = 409,318.78