Finding the Fourth Proportional to 1,311.92, 1,798.72 and 1,288.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.92 : 1,798.72 = 1,288.52 : x
2. Step 2: Convert to fraction form
   1,311.92/1,798.72 = 1,288.52/x
3. Step 3: Cross multiply
   1,311.92x = 1,798.72 × 1,288.52
4. Step 4: Simplify right side
   1,311.92x = 2,317,686.69
5. Step 5: Solve for x
   x = 2,317,686.69/1,311.92
6. Step 6: Final answer
   x = 1,766.64