Finding the Fourth Proportional to 2,557.67, 3,836.55 and 915.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557.67 : 3,836.55 = 915.40 : x
2. Step 2: Convert to fraction form
   2,557.67/3,836.55 = 915.40/x
3. Step 3: Cross multiply
   2,557.67x = 3,836.55 × 915.40
4. Step 4: Simplify right side
   2,557.67x = 3,511,958.69
5. Step 5: Solve for x
   x = 3,511,958.69/2,557.67
6. Step 6: Final answer
   x = 1,373.11