Finding the Fourth Proportional to 1,418.38, 2,128.31 and 678.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,418.38 : 2,128.31 = 678.83 : x
2. Step 2: Convert to fraction form
   1,418.38/2,128.31 = 678.83/x
3. Step 3: Cross multiply
   1,418.38x = 2,128.31 × 678.83
4. Step 4: Simplify right side
   1,418.38x = 1,444,751.73
5. Step 5: Solve for x
   x = 1,444,751.73/1,418.38
6. Step 6: Final answer
   x = 1,018.59