Finding the Fourth Proportional to 2,710.21, 4,065.42 and 861.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,710.21 : 4,065.42 = 861.28 : x
2. Step 2: Convert to fraction form
   2,710.21/4,065.42 = 861.28/x
3. Step 3: Cross multiply
   2,710.21x = 4,065.42 × 861.28
4. Step 4: Simplify right side
   2,710.21x = 3,501,464.94
5. Step 5: Solve for x
   x = 3,501,464.94/2,710.21
6. Step 6: Final answer
   x = 1,291.95