Finding the Fourth Proportional to 2,789.28, 4,185.90 and 1,328.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,789.28 : 4,185.90 = 1,328.40 : x
2. Step 2: Convert to fraction form
   2,789.28/4,185.90 = 1,328.40/x
3. Step 3: Cross multiply
   2,789.28x = 4,185.90 × 1,328.40
4. Step 4: Simplify right side
   2,789.28x = 5,560,549.56
5. Step 5: Solve for x
   x = 5,560,549.56/2,789.28
6. Step 6: Final answer
   x = 1,993.54