Finding the Fourth Proportional to 2,072.30, 3,108.02 and 685.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,072.30 : 3,108.02 = 685.31 : x
2. Step 2: Convert to fraction form
   2,072.30/3,108.02 = 685.31/x
3. Step 3: Cross multiply
   2,072.30x = 3,108.02 × 685.31
4. Step 4: Simplify right side
   2,072.30x = 2,129,960.21
5. Step 5: Solve for x
   x = 2,129,960.21/2,072.30
6. Step 6: Final answer
   x = 1,027.82