Finding the Fourth Proportional to 2,630.28, 3,942.72 and 1,328.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,630.28 : 3,942.72 = 1,328.88 : x
2. Step 2: Convert to fraction form
   2,630.28/3,942.72 = 1,328.88/x
3. Step 3: Cross multiply
   2,630.28x = 3,942.72 × 1,328.88
4. Step 4: Simplify right side
   2,630.28x = 5,239,401.75
5. Step 5: Solve for x
   x = 5,239,401.75/2,630.28
6. Step 6: Final answer
   x = 1,991.96