Finding the Fourth Proportional to 10,815.68, 16,221.12 and 3,419.20

Step by Step Solution

1. Step 1: Write the proportion equation
   10,815.68 : 16,221.12 = 3,419.20 : x
2. Step 2: Convert to fraction form
   10,815.68/16,221.12 = 3,419.20/x
3. Step 3: Cross multiply
   10,815.68x = 16,221.12 × 3,419.20
4. Step 4: Simplify right side
   10,815.68x = 55,463,253.50
5. Step 5: Solve for x
   x = 55,463,253.50/10,815.68
6. Step 6: Final answer
   x = 5,128.04