Finding the Fourth Proportional to 1,311.07, 1,965.49 and 580.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.07 : 1,965.49 = 580.25 : x
2. Step 2: Convert to fraction form
   1,311.07/1,965.49 = 580.25/x
3. Step 3: Cross multiply
   1,311.07x = 1,965.49 × 580.25
4. Step 4: Simplify right side
   1,311.07x = 1,140,469.61
5. Step 5: Solve for x
   x = 1,140,469.61/1,311.07
6. Step 6: Final answer
   x = 869.88