Finding the Fourth Proportional to 1,285.89, 1,774.42 and 986.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,285.89 : 1,774.42 = 986.60 : x
2. Step 2: Convert to fraction form
   1,285.89/1,774.42 = 986.60/x
3. Step 3: Cross multiply
   1,285.89x = 1,774.42 × 986.60
4. Step 4: Simplify right side
   1,285.89x = 1,750,640.31
5. Step 5: Solve for x
   x = 1,750,640.31/1,285.89
6. Step 6: Final answer
   x = 1,361.42