Finding the Fourth Proportional to 2,216.40, 3,328.36 and 2,128.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,216.40 : 3,328.36 = 2,128.12 : x
2. Step 2: Convert to fraction form
   2,216.40/3,328.36 = 2,128.12/x
3. Step 3: Cross multiply
   2,216.40x = 3,328.36 × 2,128.12
4. Step 4: Simplify right side
   2,216.40x = 7,083,149.48
5. Step 5: Solve for x
   x = 7,083,149.48/2,216.40
6. Step 6: Final answer
   x = 3,195.79