Finding the Fourth Proportional to 14,501.05, 20,012.85 and 8,128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   14,501.05 : 20,012.85 = 8,128.72 : x
2. Step 2: Convert to fraction form
   14,501.05/20,012.85 = 8,128.72/x
3. Step 3: Cross multiply
   14,501.05x = 20,012.85 × 8,128.72
4. Step 4: Simplify right side
   14,501.05x = 162,678,854.05
5. Step 5: Solve for x
   x = 162,678,854.05/14,501.05
6. Step 6: Final answer
   x = 11,218.42