Finding the Fourth Proportional to 2,093.56, 3,138.72 and 861.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,093.56 : 3,138.72 = 861.28 : x
2. Step 2: Convert to fraction form
   2,093.56/3,138.72 = 861.28/x
3. Step 3: Cross multiply
   2,093.56x = 3,138.72 × 861.28
4. Step 4: Simplify right side
   2,093.56x = 2,703,316.76
5. Step 5: Solve for x
   x = 2,703,316.76/2,093.56
6. Step 6: Final answer
   x = 1,291.25