Finding the Fourth Proportional to 1,398.80, 1,930.22 and 809.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.80 : 1,930.22 = 809.34 : x
2. Step 2: Convert to fraction form
   1,398.80/1,930.22 = 809.34/x
3. Step 3: Cross multiply
   1,398.80x = 1,930.22 × 809.34
4. Step 4: Simplify right side
   1,398.80x = 1,562,204.25
5. Step 5: Solve for x
   x = 1,562,204.25/1,398.80
6. Step 6: Final answer
   x = 1,116.82