Finding the Fourth Proportional to 2,086.40, 2,879.28 and 1,142.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.40 : 2,879.28 = 1,142.21 : x
2. Step 2: Convert to fraction form
   2,086.40/2,879.28 = 1,142.21/x
3. Step 3: Cross multiply
   2,086.40x = 2,879.28 × 1,142.21
4. Step 4: Simplify right side
   2,086.40x = 3,288,749.61
5. Step 5: Solve for x
   x = 3,288,749.61/2,086.40
6. Step 6: Final answer
   x = 1,576.28