Finding the Fourth Proportional to 2,557.56, 3,834.96 and 913.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557.56 : 3,834.96 = 913.20 : x
2. Step 2: Convert to fraction form
   2,557.56/3,834.96 = 913.20/x
3. Step 3: Cross multiply
   2,557.56x = 3,834.96 × 913.20
4. Step 4: Simplify right side
   2,557.56x = 3,502,085.47
5. Step 5: Solve for x
   x = 3,502,085.47/2,557.56
6. Step 6: Final answer
   x = 1,369.31