Finding the Fourth Proportional to 1,398.31, 1,929.71 and 808.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.31 : 1,929.71 = 808.88 : x
2. Step 2: Convert to fraction form
   1,398.31/1,929.71 = 808.88/x
3. Step 3: Cross multiply
   1,398.31x = 1,929.71 × 808.88
4. Step 4: Simplify right side
   1,398.31x = 1,560,896.20
5. Step 5: Solve for x
   x = 1,560,896.20/1,398.31
6. Step 6: Final answer
   x = 1,116.28