Finding the Fourth Proportional to 2,561.48, 3,840.60 and 917.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,561.48 : 3,840.60 = 917.72 : x
2. Step 2: Convert to fraction form
   2,561.48/3,840.60 = 917.72/x
3. Step 3: Cross multiply
   2,561.48x = 3,840.60 × 917.72
4. Step 4: Simplify right side
   2,561.48x = 3,524,595.43
5. Step 5: Solve for x
   x = 3,524,595.43/2,561.48
6. Step 6: Final answer
   x = 1,376.00