Finding the Fourth Proportional to 1,078.31, 1,488.23 and 686.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.31 : 1,488.23 = 686.48 : x
2. Step 2: Convert to fraction form
   1,078.31/1,488.23 = 686.48/x
3. Step 3: Cross multiply
   1,078.31x = 1,488.23 × 686.48
4. Step 4: Simplify right side
   1,078.31x = 1,021,629.26
5. Step 5: Solve for x
   x = 1,021,629.26/1,078.31
6. Step 6: Final answer
   x = 947.44