Finding the Fourth Proportional to 2,856.56, 3,943.90 and 2,557.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,856.56 : 3,943.90 = 2,557.28 : x
2. Step 2: Convert to fraction form
   2,856.56/3,943.90 = 2,557.28/x
3. Step 3: Cross multiply
   2,856.56x = 3,943.90 × 2,557.28
4. Step 4: Simplify right side
   2,856.56x = 10,085,656.59
5. Step 5: Solve for x
   x = 10,085,656.59/2,856.56
6. Step 6: Final answer
   x = 3,530.70