Finding the Fourth Proportional to 2,805.90, 4,208.37 and 831.49

Step by Step Solution

1. Step 1: Write the proportion equation
   2,805.90 : 4,208.37 = 831.49 : x
2. Step 2: Convert to fraction form
   2,805.90/4,208.37 = 831.49/x
3. Step 3: Cross multiply
   2,805.90x = 4,208.37 × 831.49
4. Step 4: Simplify right side
   2,805.90x = 3,499,196.53
5. Step 5: Solve for x
   x = 3,499,196.53/2,805.90
6. Step 6: Final answer
   x = 1,247.09