Finding the Fourth Proportional to 1,398.71, 2,099.61 and 814.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.71 : 2,099.61 = 814.38 : x
2. Step 2: Convert to fraction form
   1,398.71/2,099.61 = 814.38/x
3. Step 3: Cross multiply
   1,398.71x = 2,099.61 × 814.38
4. Step 4: Simplify right side
   1,398.71x = 1,709,880.39
5. Step 5: Solve for x
   x = 1,709,880.39/1,398.71
6. Step 6: Final answer
   x = 1,222.47