Finding the Fourth Proportional to 1,420.74, 1,960.74 and 831.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.74 : 1,960.74 = 831.12 : x
2. Step 2: Convert to fraction form
   1,420.74/1,960.74 = 831.12/x
3. Step 3: Cross multiply
   1,420.74x = 1,960.74 × 831.12
4. Step 4: Simplify right side
   1,420.74x = 1,629,610.23
5. Step 5: Solve for x
   x = 1,629,610.23/1,420.74
6. Step 6: Final answer
   x = 1,147.02