Finding the Fourth Proportional to 2,216.86, 3,326.96 and 831.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,216.86 : 3,326.96 = 831.55 : x
2. Step 2: Convert to fraction form
   2,216.86/3,326.96 = 831.55/x
3. Step 3: Cross multiply
   2,216.86x = 3,326.96 × 831.55
4. Step 4: Simplify right side
   2,216.86x = 2,766,533.59
5. Step 5: Solve for x
   x = 2,766,533.59/2,216.86
6. Step 6: Final answer
   x = 1,247.95