Finding the Fourth Proportional to 2,648.12, 3,969.60 and 1,261.08

Step by Step Solution

1. Step 1: Write the proportion equation
   2,648.12 : 3,969.60 = 1,261.08 : x
2. Step 2: Convert to fraction form
   2,648.12/3,969.60 = 1,261.08/x
3. Step 3: Cross multiply
   2,648.12x = 3,969.60 × 1,261.08
4. Step 4: Simplify right side
   2,648.12x = 5,005,976.86
5. Step 5: Solve for x
   x = 5,005,976.86/2,648.12
6. Step 6: Final answer
   x = 1,890.39