Finding the Fourth Proportional to 1,139.46, 1,707.72 and 864.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.46 : 1,707.72 = 864.72 : x
2. Step 2: Convert to fraction form
   1,139.46/1,707.72 = 864.72/x
3. Step 3: Cross multiply
   1,139.46x = 1,707.72 × 864.72
4. Step 4: Simplify right side
   1,139.46x = 1,476,699.64
5. Step 5: Solve for x
   x = 1,476,699.64/1,139.46
6. Step 6: Final answer
   x = 1,295.96