Finding the Fourth Proportional to 3,900.28, 5,382.18 and 2,221.42

Step by Step Solution

1. Step 1: Write the proportion equation
   3,900.28 : 5,382.18 = 2,221.42 : x
2. Step 2: Convert to fraction form
   3,900.28/5,382.18 = 2,221.42/x
3. Step 3: Cross multiply
   3,900.28x = 5,382.18 × 2,221.42
4. Step 4: Simplify right side
   3,900.28x = 11,956,082.30
5. Step 5: Solve for x
   x = 11,956,082.30/3,900.28
6. Step 6: Final answer
   x = 3,065.44