Finding the Fourth Proportional to 1,280.56, 1,767.42 and 783.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.56 : 1,767.42 = 783.49 : x
2. Step 2: Convert to fraction form
   1,280.56/1,767.42 = 783.49/x
3. Step 3: Cross multiply
   1,280.56x = 1,767.42 × 783.49
4. Step 4: Simplify right side
   1,280.56x = 1,384,755.90
5. Step 5: Solve for x
   x = 1,384,755.90/1,280.56
6. Step 6: Final answer
   x = 1,081.37