Finding the Fourth Proportional to 1,280.88, 1,767.56 and 721.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.88 : 1,767.56 = 721.37 : x
2. Step 2: Convert to fraction form
   1,280.88/1,767.56 = 721.37/x
3. Step 3: Cross multiply
   1,280.88x = 1,767.56 × 721.37
4. Step 4: Simplify right side
   1,280.88x = 1,275,065.57
5. Step 5: Solve for x
   x = 1,275,065.57/1,280.88
6. Step 6: Final answer
   x = 995.46