Finding the Fourth Proportional to 1,280.61, 1,768.10 and 756.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.61 : 1,768.10 = 756.81 : x
2. Step 2: Convert to fraction form
   1,280.61/1,768.10 = 756.81/x
3. Step 3: Cross multiply
   1,280.61x = 1,768.10 × 756.81
4. Step 4: Simplify right side
   1,280.61x = 1,338,111.98
5. Step 5: Solve for x
   x = 1,338,111.98/1,280.61
6. Step 6: Final answer
   x = 1,044.90