Finding the Fourth Proportional to 1,139.32, 1,571.56 and 697.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.32 : 1,571.56 = 697.28 : x
2. Step 2: Convert to fraction form
   1,139.32/1,571.56 = 697.28/x
3. Step 3: Cross multiply
   1,139.32x = 1,571.56 × 697.28
4. Step 4: Simplify right side
   1,139.32x = 1,095,817.36
5. Step 5: Solve for x
   x = 1,095,817.36/1,139.32
6. Step 6: Final answer
   x = 961.82