Finding the Fourth Proportional to 1,280.69, 1,920.15 and 654.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.69 : 1,920.15 = 654.77 : x
2. Step 2: Convert to fraction form
   1,280.69/1,920.15 = 654.77/x
3. Step 3: Cross multiply
   1,280.69x = 1,920.15 × 654.77
4. Step 4: Simplify right side
   1,280.69x = 1,257,261.42
5. Step 5: Solve for x
   x = 1,257,261.42/1,280.69
6. Step 6: Final answer
   x = 981.71