Finding the Fourth Proportional to 3,429.78, 5,144.61 and 1,121.28

Step by Step Solution

1. Step 1: Write the proportion equation
   3,429.78 : 5,144.61 = 1,121.28 : x
2. Step 2: Convert to fraction form
   3,429.78/5,144.61 = 1,121.28/x
3. Step 3: Cross multiply
   3,429.78x = 5,144.61 × 1,121.28
4. Step 4: Simplify right side
   3,429.78x = 5,768,548.30
5. Step 5: Solve for x
   x = 5,768,548.30/3,429.78
6. Step 6: Final answer
   x = 1,681.90