Finding the Fourth Proportional to 2,581.78, 3,872.69 and 1,021.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.78 : 3,872.69 = 1,021.72 : x
2. Step 2: Convert to fraction form
   2,581.78/3,872.69 = 1,021.72/x
3. Step 3: Cross multiply
   2,581.78x = 3,872.69 × 1,021.72
4. Step 4: Simplify right side
   2,581.78x = 3,956,804.83
5. Step 5: Solve for x
   x = 3,956,804.83/2,581.78
6. Step 6: Final answer
   x = 1,532.59