Finding the Fourth Proportional to 1,559.81, 2,152.54 and 861.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,559.81 : 2,152.54 = 861.23 : x
2. Step 2: Convert to fraction form
   1,559.81/2,152.54 = 861.23/x
3. Step 3: Cross multiply
   1,559.81x = 2,152.54 × 861.23
4. Step 4: Simplify right side
   1,559.81x = 1,853,838.48
5. Step 5: Solve for x
   x = 1,853,838.48/1,559.81
6. Step 6: Final answer
   x = 1,188.50