Finding the Fourth Proportional to 2,616.64, 3,921.72 and 1,228.18

Step by Step Solution

1. Step 1: Write the proportion equation
   2,616.64 : 3,921.72 = 1,228.18 : x
2. Step 2: Convert to fraction form
   2,616.64/3,921.72 = 1,228.18/x
3. Step 3: Cross multiply
   2,616.64x = 3,921.72 × 1,228.18
4. Step 4: Simplify right side
   2,616.64x = 4,816,578.07
5. Step 5: Solve for x
   x = 4,816,578.07/2,616.64
6. Step 6: Final answer
   x = 1,840.75