Finding the Fourth Proportional to 8,128.89, 11,217.27 and 5,479.89

Step by Step Solution

1. Step 1: Write the proportion equation
   8,128.89 : 11,217.27 = 5,479.89 : x
2. Step 2: Convert to fraction form
   8,128.89/11,217.27 = 5,479.89/x
3. Step 3: Cross multiply
   8,128.89x = 11,217.27 × 5,479.89
4. Step 4: Simplify right side
   8,128.89x = 61,469,405.70
5. Step 5: Solve for x
   x = 61,469,405.70/8,128.89
6. Step 6: Final answer
   x = 7,561.84