Finding the Fourth Proportional to 2,815.07, 4,219.55 and 1,391.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,815.07 : 4,219.55 = 1,391.28 : x
2. Step 2: Convert to fraction form
   2,815.07/4,219.55 = 1,391.28/x
3. Step 3: Cross multiply
   2,815.07x = 4,219.55 × 1,391.28
4. Step 4: Simplify right side
   2,815.07x = 5,870,568.57
5. Step 5: Solve for x
   x = 5,870,568.57/2,815.07
6. Step 6: Final answer
   x = 2,085.41