Finding the Fourth Proportional to 1,439.23, 1,986.15 and 809.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.23 : 1,986.15 = 809.76 : x
2. Step 2: Convert to fraction form
   1,439.23/1,986.15 = 809.76/x
3. Step 3: Cross multiply
   1,439.23x = 1,986.15 × 809.76
4. Step 4: Simplify right side
   1,439.23x = 1,608,297.38
5. Step 5: Solve for x
   x = 1,608,297.38/1,439.23
6. Step 6: Final answer
   x = 1,117.47