Finding the Fourth Proportional to 3,919.78, 5,879.72 and 998.09

Step by Step Solution

1. Step 1: Write the proportion equation
   3,919.78 : 5,879.72 = 998.09 : x
2. Step 2: Convert to fraction form
   3,919.78/5,879.72 = 998.09/x
3. Step 3: Cross multiply
   3,919.78x = 5,879.72 × 998.09
4. Step 4: Simplify right side
   3,919.78x = 5,868,489.73
5. Step 5: Solve for x
   x = 5,868,489.73/3,919.78
6. Step 6: Final answer
   x = 1,497.15