Finding the Fourth Proportional to 2,581.91, 3,872.17 and 1,120.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.91 : 3,872.17 = 1,120.72 : x
2. Step 2: Convert to fraction form
   2,581.91/3,872.17 = 1,120.72/x
3. Step 3: Cross multiply
   2,581.91x = 3,872.17 × 1,120.72
4. Step 4: Simplify right side
   2,581.91x = 4,339,618.36
5. Step 5: Solve for x
   x = 4,339,618.36/2,581.91
6. Step 6: Final answer
   x = 1,680.78