Finding the Fourth Proportional to 2,640.04, 3,956.62 and 1,078.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,640.04 : 3,956.62 = 1,078.21 : x
2. Step 2: Convert to fraction form
   2,640.04/3,956.62 = 1,078.21/x
3. Step 3: Cross multiply
   2,640.04x = 3,956.62 × 1,078.21
4. Step 4: Simplify right side
   2,640.04x = 4,266,067.25
5. Step 5: Solve for x
   x = 4,266,067.25/2,640.04
6. Step 6: Final answer
   x = 1,615.91