Finding the Fourth Proportional to 9,005.12, 12,429.72 and 5,229.20

Step by Step Solution

1. Step 1: Write the proportion equation
   9,005.12 : 12,429.72 = 5,229.20 : x
2. Step 2: Convert to fraction form
   9,005.12/12,429.72 = 5,229.20/x
3. Step 3: Cross multiply
   9,005.12x = 12,429.72 × 5,229.20
4. Step 4: Simplify right side
   9,005.12x = 64,997,491.82
5. Step 5: Solve for x
   x = 64,997,491.82/9,005.12
6. Step 6: Final answer
   x = 7,217.84