Finding the Fourth Proportional to 10,209.72, 15,311.20 and 3,969.28

Step by Step Solution

1. Step 1: Write the proportion equation
   10,209.72 : 15,311.20 = 3,969.28 : x
2. Step 2: Convert to fraction form
   10,209.72/15,311.20 = 3,969.28/x
3. Step 3: Cross multiply
   10,209.72x = 15,311.20 × 3,969.28
4. Step 4: Simplify right side
   10,209.72x = 60,774,439.94
5. Step 5: Solve for x
   x = 60,774,439.94/10,209.72
6. Step 6: Final answer
   x = 5,952.61