Finding the Fourth Proportional to 1,559.72, 2,152.41 and 861.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,559.72 : 2,152.41 = 861.09 : x
2. Step 2: Convert to fraction form
   1,559.72/2,152.41 = 861.09/x
3. Step 3: Cross multiply
   1,559.72x = 2,152.41 × 861.09
4. Step 4: Simplify right side
   1,559.72x = 1,853,430.03
5. Step 5: Solve for x
   x = 1,853,430.03/1,559.72
6. Step 6: Final answer
   x = 1,188.31