Finding the Fourth Proportional to 1,439.72, 1,986.75 and 810.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.72 : 1,986.75 = 810.28 : x
2. Step 2: Convert to fraction form
   1,439.72/1,986.75 = 810.28/x
3. Step 3: Cross multiply
   1,439.72x = 1,986.75 × 810.28
4. Step 4: Simplify right side
   1,439.72x = 1,609,822.96
5. Step 5: Solve for x
   x = 1,609,822.96/1,439.72
6. Step 6: Final answer
   x = 1,118.15