Finding the Third Proportional to 291,488 and 636,978

Step by Step Solution

1. Step 1: Write the proportion equation
   291,488 : 636,978 = 636,978 : x
2. Step 2: Convert to fraction form
   291,488/636,978 = 636,978/x
3. Step 3: Cross multiply
   291,488x = 636,978 × 636,978
4. Step 4: Simplify right side
   291,488x = 405,740,972,484
5. Step 5: Solve for x
   x = 405,740,972,484/291,488
6. Step 6: Final answer
   x = 1,391,964.58