Finding the Fourth Proportional to 10,402.72, 15,609.89 and 4,163.20

Step by Step Solution

1. Step 1: Write the proportion equation
   10,402.72 : 15,609.89 = 4,163.20 : x
2. Step 2: Convert to fraction form
   10,402.72/15,609.89 = 4,163.20/x
3. Step 3: Cross multiply
   10,402.72x = 15,609.89 × 4,163.20
4. Step 4: Simplify right side
   10,402.72x = 64,987,065.43
5. Step 5: Solve for x
   x = 64,987,065.43/10,402.72
6. Step 6: Final answer
   x = 6,247.12