Finding the Fourth Proportional to 2,557.20, 3,835.72 and 825.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557.20 : 3,835.72 = 825.76 : x
2. Step 2: Convert to fraction form
   2,557.20/3,835.72 = 825.76/x
3. Step 3: Cross multiply
   2,557.20x = 3,835.72 × 825.76
4. Step 4: Simplify right side
   2,557.20x = 3,167,384.15
5. Step 5: Solve for x
   x = 3,167,384.15/2,557.20
6. Step 6: Final answer
   x = 1,238.61