Finding the Fourth Proportional to 1,287.69, 1,776.89 and 728.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.69 : 1,776.89 = 728.18 : x
2. Step 2: Convert to fraction form
   1,287.69/1,776.89 = 728.18/x
3. Step 3: Cross multiply
   1,287.69x = 1,776.89 × 728.18
4. Step 4: Simplify right side
   1,287.69x = 1,293,883.23
5. Step 5: Solve for x
   x = 1,293,883.23/1,287.69
6. Step 6: Final answer
   x = 1,004.81