Finding the Fourth Proportional to 1,398.25, 1,929.18 and 808.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.25 : 1,929.18 = 808.71 : x
2. Step 2: Convert to fraction form
   1,398.25/1,929.18 = 808.71/x
3. Step 3: Cross multiply
   1,398.25x = 1,929.18 × 808.71
4. Step 4: Simplify right side
   1,398.25x = 1,560,147.16
5. Step 5: Solve for x
   x = 1,560,147.16/1,398.25
6. Step 6: Final answer
   x = 1,115.79