Finding the Fourth Proportional to 4,921.83, 6,789.98 and 3,128.35

Step by Step Solution

1. Step 1: Write the proportion equation
   4,921.83 : 6,789.98 = 3,128.35 : x
2. Step 2: Convert to fraction form
   4,921.83/6,789.98 = 3,128.35/x
3. Step 3: Cross multiply
   4,921.83x = 6,789.98 × 3,128.35
4. Step 4: Simplify right side
   4,921.83x = 21,241,433.93
5. Step 5: Solve for x
   x = 21,241,433.93/4,921.83
6. Step 6: Final answer
   x = 4,315.76