Finding the Fourth Proportional to 1,379.35, 2,067.47 and 686.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.35 : 2,067.47 = 686.51 : x
2. Step 2: Convert to fraction form
   1,379.35/2,067.47 = 686.51/x
3. Step 3: Cross multiply
   1,379.35x = 2,067.47 × 686.51
4. Step 4: Simplify right side
   1,379.35x = 1,419,340.57
5. Step 5: Solve for x
   x = 1,419,340.57/1,379.35
6. Step 6: Final answer
   x = 1,028.99