Finding the Fourth Proportional to 1,118.78, 1,677.83 and 425.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.78 : 1,677.83 = 425.82 : x
2. Step 2: Convert to fraction form
   1,118.78/1,677.83 = 425.82/x
3. Step 3: Cross multiply
   1,118.78x = 1,677.83 × 425.82
4. Step 4: Simplify right side
   1,118.78x = 714,451.44
5. Step 5: Solve for x
   x = 714,451.44/1,118.78
6. Step 6: Final answer
   x = 638.60