Finding the Fourth Proportional to 1,559.13, 2,151.59 and 860.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,559.13 : 2,151.59 = 860.55 : x
2. Step 2: Convert to fraction form
   1,559.13/2,151.59 = 860.55/x
3. Step 3: Cross multiply
   1,559.13x = 2,151.59 × 860.55
4. Step 4: Simplify right side
   1,559.13x = 1,851,550.77
5. Step 5: Solve for x
   x = 1,851,550.77/1,559.13
6. Step 6: Final answer
   x = 1,187.55