Finding the Fourth Proportional to 2,275.72, 3,139.54 and 1,391.24

Step by Step Solution

1. Step 1: Write the proportion equation
   2,275.72 : 3,139.54 = 1,391.24 : x
2. Step 2: Convert to fraction form
   2,275.72/3,139.54 = 1,391.24/x
3. Step 3: Cross multiply
   2,275.72x = 3,139.54 × 1,391.24
4. Step 4: Simplify right side
   2,275.72x = 4,367,853.63
5. Step 5: Solve for x
   x = 4,367,853.63/2,275.72
6. Step 6: Final answer
   x = 1,919.33