Finding the Fourth Proportional to 1,085.56, 1,629.15 and 871.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.56 : 1,629.15 = 871.72 : x
2. Step 2: Convert to fraction form
   1,085.56/1,629.15 = 871.72/x
3. Step 3: Cross multiply
   1,085.56x = 1,629.15 × 871.72
4. Step 4: Simplify right side
   1,085.56x = 1,420,162.64
5. Step 5: Solve for x
   x = 1,420,162.64/1,085.56
6. Step 6: Final answer
   x = 1,308.23