Finding the Fourth Proportional to 6,456.20, 9,689.70 and 3,172.10

Step by Step Solution

1. Step 1: Write the proportion equation
   6,456.20 : 9,689.70 = 3,172.10 : x
2. Step 2: Convert to fraction form
   6,456.20/9,689.70 = 3,172.10/x
3. Step 3: Cross multiply
   6,456.20x = 9,689.70 × 3,172.10
4. Step 4: Simplify right side
   6,456.20x = 30,736,697.37
5. Step 5: Solve for x
   x = 30,736,697.37/6,456.20
6. Step 6: Final answer
   x = 4,760.80