Finding the Fourth Proportional to 2,340.90, 3,510.21 and 839.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,340.90 : 3,510.21 = 839.40 : x
2. Step 2: Convert to fraction form
   2,340.90/3,510.21 = 839.40/x
3. Step 3: Cross multiply
   2,340.90x = 3,510.21 × 839.40
4. Step 4: Simplify right side
   2,340.90x = 2,946,470.27
5. Step 5: Solve for x
   x = 2,946,470.27/2,340.90
6. Step 6: Final answer
   x = 1,258.69