Finding the Fourth Proportional to 1,273.56, 1,908.72 and 687.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,273.56 : 1,908.72 = 687.12 : x
2. Step 2: Convert to fraction form
   1,273.56/1,908.72 = 687.12/x
3. Step 3: Cross multiply
   1,273.56x = 1,908.72 × 687.12
4. Step 4: Simplify right side
   1,273.56x = 1,311,519.69
5. Step 5: Solve for x
   x = 1,311,519.69/1,273.56
6. Step 6: Final answer
   x = 1,029.81