Finding the Fourth Proportional to 2,560, 3,840.72 and 1,261.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,560 : 3,840.72 = 1,261.12 : x
2. Step 2: Convert to fraction form
   2,560/3,840.72 = 1,261.12/x
3. Step 3: Cross multiply
   2,560x = 3,840.72 × 1,261.12
4. Step 4: Simplify right side
   2,560x = 4,843,608.81
5. Step 5: Solve for x
   x = 4,843,608.81/2,560
6. Step 6: Final answer
   x = 1,892.03