Finding the Fourth Proportional to 1,439.32, 1,986.21 and 809.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.32 : 1,986.21 = 809.87 : x
2. Step 2: Convert to fraction form
   1,439.32/1,986.21 = 809.87/x
3. Step 3: Cross multiply
   1,439.32x = 1,986.21 × 809.87
4. Step 4: Simplify right side
   1,439.32x = 1,608,571.89
5. Step 5: Solve for x
   x = 1,608,571.89/1,439.32
6. Step 6: Final answer
   x = 1,117.59