Finding the Fourth Proportional to 2,078.36, 3,115.46 and 980.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,078.36 : 3,115.46 = 980.78 : x
2. Step 2: Convert to fraction form
   2,078.36/3,115.46 = 980.78/x
3. Step 3: Cross multiply
   2,078.36x = 3,115.46 × 980.78
4. Step 4: Simplify right side
   2,078.36x = 3,055,567.73
5. Step 5: Solve for x
   x = 3,055,567.73/2,078.36
6. Step 6: Final answer
   x = 1,470.18