Finding the Fourth Proportional to 1,559.21, 2,151.69 and 860.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,559.21 : 2,151.69 = 860.54 : x
2. Step 2: Convert to fraction form
   1,559.21/2,151.69 = 860.54/x
3. Step 3: Cross multiply
   1,559.21x = 2,151.69 × 860.54
4. Step 4: Simplify right side
   1,559.21x = 1,851,615.31
5. Step 5: Solve for x
   x = 1,851,615.31/1,559.21
6. Step 6: Final answer
   x = 1,187.53