Finding the Fourth Proportional to 1,288.19, 1,777.89 and 728.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.19 : 1,777.89 = 728.88 : x
2. Step 2: Convert to fraction form
   1,288.19/1,777.89 = 728.88/x
3. Step 3: Cross multiply
   1,288.19x = 1,777.89 × 728.88
4. Step 4: Simplify right side
   1,288.19x = 1,295,868.46
5. Step 5: Solve for x
   x = 1,295,868.46/1,288.19
6. Step 6: Final answer
   x = 1,005.96