Finding the Fourth Proportional to 1,288.31, 1,777.73 and 728.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.31 : 1,777.73 = 728.69 : x
2. Step 2: Convert to fraction form
   1,288.31/1,777.73 = 728.69/x
3. Step 3: Cross multiply
   1,288.31x = 1,777.73 × 728.69
4. Step 4: Simplify right side
   1,288.31x = 1,295,401.54
5. Step 5: Solve for x
   x = 1,295,401.54/1,288.31
6. Step 6: Final answer
   x = 1,005.51