Finding the Fourth Proportional to 7,128.52, 10,686.78 and 3,231.88

Step by Step Solution

1. Step 1: Write the proportion equation
   7,128.52 : 10,686.78 = 3,231.88 : x
2. Step 2: Convert to fraction form
   7,128.52/10,686.78 = 3,231.88/x
3. Step 3: Cross multiply
   7,128.52x = 10,686.78 × 3,231.88
4. Step 4: Simplify right side
   7,128.52x = 34,538,390.55
5. Step 5: Solve for x
   x = 34,538,390.55/7,128.52
6. Step 6: Final answer
   x = 4,845.10