Finding the Fourth Proportional to 2,580.78, 3,871.19 and 1,020.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,580.78 : 3,871.19 = 1,020.72 : x
2. Step 2: Convert to fraction form
   2,580.78/3,871.19 = 1,020.72/x
3. Step 3: Cross multiply
   2,580.78x = 3,871.19 × 1,020.72
4. Step 4: Simplify right side
   2,580.78x = 3,951,401.06
5. Step 5: Solve for x
   x = 3,951,401.06/2,580.78
6. Step 6: Final answer
   x = 1,531.09