Finding the Fourth Proportional to 1,439.47, 1,986.28 and 809.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.47 : 1,986.28 = 809.92 : x
2. Step 2: Convert to fraction form
   1,439.47/1,986.28 = 809.92/x
3. Step 3: Cross multiply
   1,439.47x = 1,986.28 × 809.92
4. Step 4: Simplify right side
   1,439.47x = 1,608,727.90
5. Step 5: Solve for x
   x = 1,608,727.90/1,439.47
6. Step 6: Final answer
   x = 1,117.58