Finding the Fourth Proportional to 2,561.86, 3,840.36 and 917.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,561.86 : 3,840.36 = 917.56 : x
2. Step 2: Convert to fraction form
   2,561.86/3,840.36 = 917.56/x
3. Step 3: Cross multiply
   2,561.86x = 3,840.36 × 917.56
4. Step 4: Simplify right side
   2,561.86x = 3,523,760.72
5. Step 5: Solve for x
   x = 3,523,760.72/2,561.86
6. Step 6: Final answer
   x = 1,375.47