Finding the Fourth Proportional to 1,439.46, 1,986.30 and 809.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.46 : 1,986.30 = 809.91 : x
2. Step 2: Convert to fraction form
   1,439.46/1,986.30 = 809.91/x
3. Step 3: Cross multiply
   1,439.46x = 1,986.30 × 809.91
4. Step 4: Simplify right side
   1,439.46x = 1,608,724.23
5. Step 5: Solve for x
   x = 1,608,724.23/1,439.46
6. Step 6: Final answer
   x = 1,117.59