Finding the Fourth Proportional to 2,147.31, 3,221.37 and 686.07

Step by Step Solution

1. Step 1: Write the proportion equation
   2,147.31 : 3,221.37 = 686.07 : x
2. Step 2: Convert to fraction form
   2,147.31/3,221.37 = 686.07/x
3. Step 3: Cross multiply
   2,147.31x = 3,221.37 × 686.07
4. Step 4: Simplify right side
   2,147.31x = 2,210,085.32
5. Step 5: Solve for x
   x = 2,210,085.32/2,147.31
6. Step 6: Final answer
   x = 1,029.23