Finding the Fourth Proportional to 638,978, 881,789.64 and 356,354

Step by Step Solution

1. Step 1: Write the proportion equation
   638,978 : 881,789.64 = 356,354 : x
2. Step 2: Convert to fraction form
   638,978/881,789.64 = 356,354/x
3. Step 3: Cross multiply
   638,978x = 881,789.64 × 356,354
4. Step 4: Simplify right side
   638,978x = 314,229,265,372.56
5. Step 5: Solve for x
   x = 314,229,265,372.56/638,978
6. Step 6: Final answer
   x = 491,768.52