Finding the Fourth Proportional to 2,581.91, 3,870.20 and 1,021.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.91 : 3,870.20 = 1,021.28 : x
2. Step 2: Convert to fraction form
   2,581.91/3,870.20 = 1,021.28/x
3. Step 3: Cross multiply
   2,581.91x = 3,870.20 × 1,021.28
4. Step 4: Simplify right side
   2,581.91x = 3,952,557.86
5. Step 5: Solve for x
   x = 3,952,557.86/2,581.91
6. Step 6: Final answer
   x = 1,530.87