Finding the Fourth Proportional to 1,421.57, 1,961.46 and 831.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.57 : 1,961.46 = 831.98 : x
2. Step 2: Convert to fraction form
   1,421.57/1,961.46 = 831.98/x
3. Step 3: Cross multiply
   1,421.57x = 1,961.46 × 831.98
4. Step 4: Simplify right side
   1,421.57x = 1,631,900.39
5. Step 5: Solve for x
   x = 1,631,900.39/1,421.57
6. Step 6: Final answer
   x = 1,147.95