Finding the Fourth Proportional to 1,439.71, 1,986.78 and 810.19

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.71 : 1,986.78 = 810.19 : x
2. Step 2: Convert to fraction form
   1,439.71/1,986.78 = 810.19/x
3. Step 3: Cross multiply
   1,439.71x = 1,986.78 × 810.19
4. Step 4: Simplify right side
   1,439.71x = 1,609,669.29
5. Step 5: Solve for x
   x = 1,609,669.29/1,439.71
6. Step 6: Final answer
   x = 1,118.05