Finding the Third Proportional to 290,387.25 and 636,664.50

Step by Step Solution

1. Step 1: Write the proportion equation
   290,387.25 : 636,664.50 = 636,664.50 : x
2. Step 2: Convert to fraction form
   290,387.25/636,664.50 = 636,664.50/x
3. Step 3: Cross multiply
   290,387.25x = 636,664.50 × 636,664.50
4. Step 4: Simplify right side
   290,387.25x = 405,341,685,560.25
5. Step 5: Solve for x
   x = 405,341,685,560.25/290,387.25
6. Step 6: Final answer
   x = 1,395,865.99