Finding the Fourth Proportional to 1,078.62, 1,489.72 and 728.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.62 : 1,489.72 = 728.70 : x
2. Step 2: Convert to fraction form
   1,078.62/1,489.72 = 728.70/x
3. Step 3: Cross multiply
   1,078.62x = 1,489.72 × 728.70
4. Step 4: Simplify right side
   1,078.62x = 1,085,558.96
5. Step 5: Solve for x
   x = 1,085,558.96/1,078.62
6. Step 6: Final answer
   x = 1,006.43