Finding the Fourth Proportional to 1,139.46, 1,571.76 and 697.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.46 : 1,571.76 = 697.20 : x
2. Step 2: Convert to fraction form
   1,139.46/1,571.76 = 697.20/x
3. Step 3: Cross multiply
   1,139.46x = 1,571.76 × 697.20
4. Step 4: Simplify right side
   1,139.46x = 1,095,831.07
5. Step 5: Solve for x
   x = 1,095,831.07/1,139.46
6. Step 6: Final answer
   x = 961.71