Finding the Fourth Proportional to 2,071.88, 3,107.91 and 685.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.88 : 3,107.91 = 685.30 : x
2. Step 2: Convert to fraction form
   2,071.88/3,107.91 = 685.30/x
3. Step 3: Cross multiply
   2,071.88x = 3,107.91 × 685.30
4. Step 4: Simplify right side
   2,071.88x = 2,129,850.72
5. Step 5: Solve for x
   x = 2,129,850.72/2,071.88
6. Step 6: Final answer
   x = 1,027.98