Finding the Fourth Proportional to 2,689.42, 4,034.58 and 840.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,689.42 : 4,034.58 = 840.72 : x
2. Step 2: Convert to fraction form
   2,689.42/4,034.58 = 840.72/x
3. Step 3: Cross multiply
   2,689.42x = 4,034.58 × 840.72
4. Step 4: Simplify right side
   2,689.42x = 3,391,952.10
5. Step 5: Solve for x
   x = 3,391,952.10/2,689.42
6. Step 6: Final answer
   x = 1,261.22