Finding the Fourth Proportional to 3,896.47, 5,377.20 and 2,128.08

Step by Step Solution

1. Step 1: Write the proportion equation
   3,896.47 : 5,377.20 = 2,128.08 : x
2. Step 2: Convert to fraction form
   3,896.47/5,377.20 = 2,128.08/x
3. Step 3: Cross multiply
   3,896.47x = 5,377.20 × 2,128.08
4. Step 4: Simplify right side
   3,896.47x = 11,443,111.78
5. Step 5: Solve for x
   x = 11,443,111.78/3,896.47
6. Step 6: Final answer
   x = 2,936.79