Finding the Fourth Proportional to 2,640.16, 3,959.78 and 996.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,640.16 : 3,959.78 = 996.72 : x
2. Step 2: Convert to fraction form
   2,640.16/3,959.78 = 996.72/x
3. Step 3: Cross multiply
   2,640.16x = 3,959.78 × 996.72
4. Step 4: Simplify right side
   2,640.16x = 3,946,791.92
5. Step 5: Solve for x
   x = 3,946,791.92/2,640.16
6. Step 6: Final answer
   x = 1,494.91