Finding the Fourth Proportional to 2,275.39, 3,139.59 and 1,280.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,275.39 : 3,139.59 = 1,280.71 : x
2. Step 2: Convert to fraction form
   2,275.39/3,139.59 = 1,280.71/x
3. Step 3: Cross multiply
   2,275.39x = 3,139.59 × 1,280.71
4. Step 4: Simplify right side
   2,275.39x = 4,020,904.31
5. Step 5: Solve for x
   x = 4,020,904.31/2,275.39
6. Step 6: Final answer
   x = 1,767.13