Finding the Fourth Proportional to 1,421.16, 1,961.46 and 831.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.16 : 1,961.46 = 831.84 : x
2. Step 2: Convert to fraction form
   1,421.16/1,961.46 = 831.84/x
3. Step 3: Cross multiply
   1,421.16x = 1,961.46 × 831.84
4. Step 4: Simplify right side
   1,421.16x = 1,631,620.89
5. Step 5: Solve for x
   x = 1,631,620.89/1,421.16
6. Step 6: Final answer
   x = 1,148.09