Finding the Fourth Proportional to 1,439.17, 1,986.22 and 809.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.17 : 1,986.22 = 809.72 : x
2. Step 2: Convert to fraction form
   1,439.17/1,986.22 = 809.72/x
3. Step 3: Cross multiply
   1,439.17x = 1,986.22 × 809.72
4. Step 4: Simplify right side
   1,439.17x = 1,608,282.06
5. Step 5: Solve for x
   x = 1,608,282.06/1,439.17
6. Step 6: Final answer
   x = 1,117.51