Finding the Fourth Proportional to 1,439.55, 1,986.50 and 810.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.55 : 1,986.50 = 810.09 : x
2. Step 2: Convert to fraction form
   1,439.55/1,986.50 = 810.09/x
3. Step 3: Cross multiply
   1,439.55x = 1,986.50 × 810.09
4. Step 4: Simplify right side
   1,439.55x = 1,609,245.81
5. Step 5: Solve for x
   x = 1,609,245.81/1,439.55
6. Step 6: Final answer
   x = 1,117.88