Finding the Fourth Proportional to 1,139.10, 1,709.37 and 728.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.10 : 1,709.37 = 728.52 : x
2. Step 2: Convert to fraction form
   1,139.10/1,709.37 = 728.52/x
3. Step 3: Cross multiply
   1,139.10x = 1,709.37 × 728.52
4. Step 4: Simplify right side
   1,139.10x = 1,245,310.23
5. Step 5: Solve for x
   x = 1,245,310.23/1,139.10
6. Step 6: Final answer
   x = 1,093.24