Finding the Fourth Proportional to 1,139.38, 1,571.54 and 1,101.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.38 : 1,571.54 = 1,101.28 : x
2. Step 2: Convert to fraction form
   1,139.38/1,571.54 = 1,101.28/x
3. Step 3: Cross multiply
   1,139.38x = 1,571.54 × 1,101.28
4. Step 4: Simplify right side
   1,139.38x = 1,730,708.37
5. Step 5: Solve for x
   x = 1,730,708.37/1,139.38
6. Step 6: Final answer
   x = 1,518.99