Finding the Fourth Proportional to 1,287.31, 1,776.69 and 728.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.31 : 1,776.69 = 728.02 : x
2. Step 2: Convert to fraction form
   1,287.31/1,776.69 = 728.02/x
3. Step 3: Cross multiply
   1,287.31x = 1,776.69 × 728.02
4. Step 4: Simplify right side
   1,287.31x = 1,293,465.85
5. Step 5: Solve for x
   x = 1,293,465.85/1,287.31
6. Step 6: Final answer
   x = 1,004.78