Finding the Fourth Proportional to 2,559.50, 3,839.60 and 915.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,559.50 : 3,839.60 = 915.70 : x
2. Step 2: Convert to fraction form
   2,559.50/3,839.60 = 915.70/x
3. Step 3: Cross multiply
   2,559.50x = 3,839.60 × 915.70
4. Step 4: Simplify right side
   2,559.50x = 3,515,921.72
5. Step 5: Solve for x
   x = 3,515,921.72/2,559.50
6. Step 6: Final answer
   x = 1,373.68