Finding the Fourth Proportional to 7,128.76, 9,837.72 and 3,942.28

Step by Step Solution

1. Step 1: Write the proportion equation
   7,128.76 : 9,837.72 = 3,942.28 : x
2. Step 2: Convert to fraction form
   7,128.76/9,837.72 = 3,942.28/x
3. Step 3: Cross multiply
   7,128.76x = 9,837.72 × 3,942.28
4. Step 4: Simplify right side
   7,128.76x = 38,783,046.80
5. Step 5: Solve for x
   x = 38,783,046.80/7,128.76
6. Step 6: Final answer
   x = 5,440.36