Finding the Fourth Proportional to 1,420.88, 1,960.84 and 831.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.88 : 1,960.84 = 831.84 : x
2. Step 2: Convert to fraction form
   1,420.88/1,960.84 = 831.84/x
3. Step 3: Cross multiply
   1,420.88x = 1,960.84 × 831.84
4. Step 4: Simplify right side
   1,420.88x = 1,631,105.15
5. Step 5: Solve for x
   x = 1,631,105.15/1,420.88
6. Step 6: Final answer
   x = 1,147.95