Finding the Fourth Proportional to 2,275.21, 3,139.75 and 1,280.49

Step by Step Solution

1. Step 1: Write the proportion equation
   2,275.21 : 3,139.75 = 1,280.49 : x
2. Step 2: Convert to fraction form
   2,275.21/3,139.75 = 1,280.49/x
3. Step 3: Cross multiply
   2,275.21x = 3,139.75 × 1,280.49
4. Step 4: Simplify right side
   2,275.21x = 4,020,418.48
5. Step 5: Solve for x
   x = 4,020,418.48/2,275.21
6. Step 6: Final answer
   x = 1,767.05