Finding the Fourth Proportional to 1,311.55, 1,966.10 and 580.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.55 : 1,966.10 = 580.73 : x
2. Step 2: Convert to fraction form
   1,311.55/1,966.10 = 580.73/x
3. Step 3: Cross multiply
   1,311.55x = 1,966.10 × 580.73
4. Step 4: Simplify right side
   1,311.55x = 1,141,760.52
5. Step 5: Solve for x
   x = 1,141,760.52/1,311.55
6. Step 6: Final answer
   x = 870.54