Finding the Fourth Proportional to 2,019.80, 2,787.40 and 1,223.38

Step by Step Solution

1. Step 1: Write the proportion equation
   2,019.80 : 2,787.40 = 1,223.38 : x
2. Step 2: Convert to fraction form
   2,019.80/2,787.40 = 1,223.38/x
3. Step 3: Cross multiply
   2,019.80x = 2,787.40 × 1,223.38
4. Step 4: Simplify right side
   2,019.80x = 3,410,049.41
5. Step 5: Solve for x
   x = 3,410,049.41/2,019.80
6. Step 6: Final answer
   x = 1,688.31