Finding the Fourth Proportional to 1,281.56, 1,768.10 and 839.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,281.56 : 1,768.10 = 839.72 : x
2. Step 2: Convert to fraction form
   1,281.56/1,768.10 = 839.72/x
3. Step 3: Cross multiply
   1,281.56x = 1,768.10 × 839.72
4. Step 4: Simplify right side
   1,281.56x = 1,484,708.93
5. Step 5: Solve for x
   x = 1,484,708.93/1,281.56
6. Step 6: Final answer
   x = 1,158.52