Finding the Fourth Proportional to 1,283.78, 1,771.30 and 1,085.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,283.78 : 1,771.30 = 1,085.42 : x
2. Step 2: Convert to fraction form
   1,283.78/1,771.30 = 1,085.42/x
3. Step 3: Cross multiply
   1,283.78x = 1,771.30 × 1,085.42
4. Step 4: Simplify right side
   1,283.78x = 1,922,604.45
5. Step 5: Solve for x
   x = 1,922,604.45/1,283.78
6. Step 6: Final answer
   x = 1,497.61