Finding the Fourth Proportional to 2,557, 3,833.21 and 913.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557 : 3,833.21 = 913.31 : x
2. Step 2: Convert to fraction form
   2,557/3,833.21 = 913.31/x
3. Step 3: Cross multiply
   2,557x = 3,833.21 × 913.31
4. Step 4: Simplify right side
   2,557x = 3,500,909.03
5. Step 5: Solve for x
   x = 3,500,909.03/2,557
6. Step 6: Final answer
   x = 1,369.15