Finding the Fourth Proportional to 1,398.04, 1,929.33 and 808.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.04 : 1,929.33 = 808.78 : x
2. Step 2: Convert to fraction form
   1,398.04/1,929.33 = 808.78/x
3. Step 3: Cross multiply
   1,398.04x = 1,929.33 × 808.78
4. Step 4: Simplify right side
   1,398.04x = 1,560,403.52
5. Step 5: Solve for x
   x = 1,560,403.52/1,398.04
6. Step 6: Final answer
   x = 1,116.14