Finding the Fourth Proportional to 1,139.56, 1,571.64 and 697.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.56 : 1,571.64 = 697.32 : x
2. Step 2: Convert to fraction form
   1,139.56/1,571.64 = 697.32/x
3. Step 3: Cross multiply
   1,139.56x = 1,571.64 × 697.32
4. Step 4: Simplify right side
   1,139.56x = 1,095,936.00
5. Step 5: Solve for x
   x = 1,095,936.00/1,139.56
6. Step 6: Final answer
   x = 961.72