Finding the Fourth Proportional to 1,439.72, 1,986.62 and 810.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.72 : 1,986.62 = 810.22 : x
2. Step 2: Convert to fraction form
   1,439.72/1,986.62 = 810.22/x
3. Step 3: Cross multiply
   1,439.72x = 1,986.62 × 810.22
4. Step 4: Simplify right side
   1,439.72x = 1,609,590.24
5. Step 5: Solve for x
   x = 1,609,590.24/1,439.72
6. Step 6: Final answer
   x = 1,117.99