Finding the Fourth Proportional to 2,071.83, 3,107.82 and 685.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.83 : 3,107.82 = 685.20 : x
2. Step 2: Convert to fraction form
   2,071.83/3,107.82 = 685.20/x
3. Step 3: Cross multiply
   2,071.83x = 3,107.82 × 685.20
4. Step 4: Simplify right side
   2,071.83x = 2,129,478.26
5. Step 5: Solve for x
   x = 2,129,478.26/2,071.83
6. Step 6: Final answer
   x = 1,027.82